Do heavier coaster cars go faster? Why?
neilk...@my-deja.com
My elementary-school-age child and I are doing a school science
project. We need your help!
Here is our question, which is also the title of our project:
"Do heavier roller coaster cars go faster?"
We built a model and in our experiment, we found that a coaster car
with added weights goes faster.
So here's our question:
WHY do heavier coaster cars go faster?
We know that Galileo discovered that heavy and light objects fall at
the same speed.
So why does a heavy coaster car go faster than a light coaster? Does
the weight help to break the friction holding the coaster car in place?
Please post your answer to the newsgroup and/or e-mail me at:
neilkoomen (at) hotmail (dot) com
Thank you in advance for your answer. If you could answer by Monday
night (2/7/2000), we would greatly appreciate it.
Thank you,
Neil
Sent via Deja.com http://www.deja.com/
Before you buy.
P L
My guess is that it has to do with a heavier train staying on the tracks
more. The more play there is (friction, pitching and yawing side to side),
the slower the train goes.
James Draeger
> So here's our question:
>
> WHY do heavier coaster cars go faster?
>
> We know that Galileo discovered that heavy and light objects fall at
> the same speed.
>
> So why does a heavy coaster car go faster than a light coaster? Does
> the weight help to break the friction holding the coaster car in place?
It should be due to the fact that the heavier train will have more
momentum. That is, it would take more force to stop it's forward
movement. Momentum is calculated by multiplying the mass of the vehicle by
it's speed. Obviously the beginning speed for both the heavier and lighter
trains would be the same, but the masses would differ. And that is where
the larger amount of momentum would come from in the heavier train.
Think about how when a car and a semi collide the car usually travels much
farther than the truck. This is because the truck is many times more
massive and therefore has more momentum. More momentum means that it is
harder to slow the truck down than the car.
(I think)
--
James Draeger
draegs @ mindspring.com C G & C P
*******************************************************************
* "a friend is always good to have, *
* but a lovers kiss is better than angels raining down at me" *
*******************************************************************
David Keenan
> neilk...@my-deja.com wrote:
>
> > So here's our question:
> >
> > WHY do heavier coaster cars go faster?
> >
> > We know that Galileo discovered that heavy and light objects fall at
> > the same speed.
> >
> > So why does a heavy coaster car go faster than a light coaster? Does
> > the weight help to break the friction holding the coaster car in place?
>
> It should be due to the fact that the heavier train will have more
> momentum. That is, it would take more force to stop it's forward
> movement. Momentum is calculated by multiplying the mass of the vehicle by
> it's speed. Obviously the beginning speed for both the heavier and lighter
> trains would be the same, but the masses would differ. And that is where
> the larger amount of momentum would come from in the heavier train.
>
> Think about how when a car and a semi collide the car usually travels much
> farther than the truck. This is because the truck is many times more
> massive and therefore has more momentum. More momentum means that it is
> harder to slow the truck down than the car.
>
> (I think)
Sounds like what I thought of when I read this--Gravity is constant, so both
a one-car coaster train and a 7-car train would (friction not counted)
accelerate the same down the first hill, but the momentum of the big train
would 'push' it through the dip and further up the next hill at a better rate
than the little train would. If you play RCT, you can see this to a degree
when you build a coaster with a small train, and the train crawls through
a loop, but you lengthen the train and now it will go through faster through
that same loop.
Also compare a railroad train to a bicycle. If you (on the bike) and the
train start at the same time and 'match' each other, you're accelerating
at the same rate, but when you go start up a hill, and coast, you would
come to a stop, but the train would cruise through on its momentum for
quite a while.
Dave Sandborg
massive train as much. If not for these forces, a coaster train would go
at the same speed regardless of its mass. You are correct about Galileo's
principle.
--
Dave Sandborg
Remove Spam-away to respond via e-mail.
DJ Gallup and Richard Allen
>
> Hi:
>
> My elementary-school-age child and I are doing a school science
> project. We need your help!
>
> Here is our question, which is also the title of our project:
>
> "Do heavier roller coaster cars go faster?"
>
wouldn't make much of a difference with speed (if any). It is true that
you would build more momentum, however, I believe that woodies have more
friction, and the friction would just slow down the train. The
difference is speeds between a light and a heavy train would be
neglegible.
On a steel coaster, however, there is normally less friction (if only
slightly less) due to the smooth wheels and tracks, so a heavier train
would probably go slightly faster.
If you want a really scientific answer, I'm sure there are many people
on r.r-c who are much more "into" Physics than I am, they can help you
further.
D.J.
Dave Althoff Jr
Someone else, and I don't remember who, noted that ignoring friction the
acceleration is exactly the same for a heavy train as for a light one.
This is true, but ignoring resistances the heavy train will also coast
just as far and just as fast up the second hill. Friction is the key
here. The heavier train has more momentum...that is, more total energy.
Some of the resistive effects do not vary with mass, and therefore will
result in the same total energy loss regardless of the mass of the train,
so the train with the most energy will retain the most total energy after
the losses, meaning it will move faster after the first drop.
--Dave Althoff, Jr.
--
/^\ _ _ _*** Closed for the season ***
/XXX\ /X\ /X\_ _ /X\__ _ _ _____
/XXXXX\ /XXX\ _/XXXX\_ /X\ /XXXXX\ /X\ /X\ /XXXXX
_/XXXXXXX\__/XXXXX\/XXXXXXXX\_/XXX\_/XXXXXXX\__/XXX\_/XXX\_/\_/XXXXXX
J. Rasmussen
Ken wrote in message <20000206224457...@ng-cc1.aol.com>...
>>
>>"Do heavier roller coaster cars go faster?"
>
>
"kinergardiners"???! I assume you meant kindergartners or kindergarteners
(both forms are acceptable).
The original post said "elementary-school-age child" which, in some school
districts, could be up to the eighth grade.
For what it's worth, several of the children in my preschool class are
fascinated with roller coasters. They build them all the time with unit
blocks and use matchbox cars or build small lego cars for the trains. They
also enjoyed looking at my roller coaster books and have many questions
about them.
-Janna
Locoboy
> For what it's worth, several of the children in my preschool class are
> fascinated with roller coasters. They build them all the time with unit
> blocks and use matchbox cars or build small lego cars for the trains. They
> also enjoyed looking at my roller coaster books and have many questions
> about them.
>
> -Janna
Hehe, it's nice to hear that little kids of that age are doing the same
kinda stuff I was doing when I was that age. :-) Please Janna, if you
have the time during your busy day, tell your students about the
American Coaster Enthusiasts. We always welcome the next generation of
coaster fans. :-)
Meme901
the lighter train meaning that it will not slow down quite as quickly as a
smaller train whe travel;ling up a hill. Also, a longer train will travel
faster because even if the front part of the car has leveled out, the back
could still be travelling downhill, causing the train to continue picking up
speed.
. .
l
\_/
Charles Nungester
>wouldn't make much of a difference with speed (if any). It is true that
>you would build more momentum, however, I believe that woodies have more
>friction, and the friction would just slow down the train. The
>difference is speeds between a light and a heavy train would be
>neglegible.
>
>On a steel coaster, however, there is normally less friction (if only
>slightly less) due to the smooth wheels and tracks, so a heavier train
>would probably go slightly faster.
>
>If you want a really scientific answer, I'm sure there are many people
>on r.r-c who are much more "into" Physics than I am, they can help you
>further.
>
>D.J.
>
>
woodies provide less friction than steel coasters
Chuck. Member of Ace since 2/03/00
http://members.aol.com/coasterfanatic/CoasterFaNaTiCsFoRuMindex.html
Ken
Jeff & Sandy
In short, almost all of the RE: that have been posted point to the most
simple
of engineering concepts...the first of which is *A little bit of knowledge
is a dangerous thing* :o)
The entire answer is much too complicated for K12 levels ( and most high
schoolers that I know ).
In short, your measurements are of total energy which are proportional to
the mass ( weight ). The
higher the weight, the more energyretained, the higher the train climbs (
to a point )....this is where it gets
complicated and where I'll end this post.
Jeff
- That's Just My Opinion, I could be Wrong -
neilk...@my-deja.com wrote:
> Hi:
>
> My elementary-school-age child and I are doing a school science
> project. We need your help!
>
> Here is our question, which is also the title of our project:
>
> "Do heavier roller coaster cars go faster?"
>
> We built a model and in our experiment, we found that a coaster car
> with added weights goes faster.
>
> So here's our question:
>
> WHY do heavier coaster cars go faster?
>
> We know that Galileo discovered that heavy and light objects fall at
> the same speed.
>
> So why does a heavy coaster car go faster than a light coaster? Does
> the weight help to break the friction holding the coaster car in place?
>
Locoboy
> My daugher is now almost 2 and one half years old. She gets SOOO excited
> whenever she grabs one of my coaster newsletters or magazines now, she
> won't give them up! She's the only kid I know that when she sees a bridge
> with a truss like structure points and says, "Daddy, daddy....a
> rollercoaster". She has ridden 7 coasters now too, and I hope more next
> year if she gets over her fear. Sometimes they scare her....
>
> Ted Ansley
> **Rollercoaster Fan<atic>**
> ansl...@earthlink.net
Hehe, cool story Ted! I can see that she's being raised with the right
family (coaster) values! :-)
Ted Ansley
Dave Sandborg
<jd...@postnet.com> wrote:
> The entire answer is much too complicated for K12 levels ( and most high
> schoolers that I know ).
If you mean going through quantitative derivations of precisely how
friction would affect the train, probably. But a qualitative, but correct,
answer is perfectly within K12 capabilities.
Wolf
> > schoolers that I know ).
>
> If you mean going through quantitative derivations of precisely how
> friction would affect the train, probably. But a qualitative, but
correct,
> answer is perfectly within K12 capabilities.
in a perfect world, with no drag or friction, then no, weight does not
matter.
In the real world - yes, it does. The speed increase is do to the inertia
and momentum of the train better overcomign drag and friction. Note - this
is why fully-loaded trains are run in less than optimum conditions. Quite
simply, the unloaded train doesn't have the momentum to make some of the
hills.
--
|\-/|
<0 0>
=(o)=
-Wolf
V. Canfield
> In short, almost all of the RE: that have been posted point to the most
> simple
> of engineering concepts...the first of which is *A little bit of knowledge
> is a dangerous thing* :o)
> The entire answer is much too complicated for K12 levels ( and most high
> schoolers that I know ).
> In short, your measurements are of total energy which are proportional to
> the mass ( weight ). The
> higher the weight, the more energy retained, the higher the train climbs (
> to a point )....this is where it gets
> complicated and where I'll end this post.
I'll give this one a try. It is too complicated to discuss the subject in
terms of momentum, and it is simpler if we do not even bring energy into it.
We do need one equation:
F = m * a
If the increase in force (F) is proportional to the mass (m), the acceleration
(a) will remain the same. Since gravitational forces are strictly
proportional to mass, the acceleration and hence velocity of a rollercoaster
train would be independent of mass if there were no frictional forces, as has
previouly been noted. Gravity will increase the speed of the train when it is
descending, and decrease it when it is ascending.
Frictional forces, which can only slow the train, complicate things a lot.
Frictional forces associated with rolling, sliding, etc. should be
approximately, proportional to loading forces. That is, if the forces
pressing the train against the track are doubled, these frictional forces will
be approximately doubled as well. Since loading is proportional to train
mass, these forces should cause similar decelerations in light and heavy
trains.
Wind resistance or drag, on the other hand, depends on the shape, but not
the mass, of the coaster train. A train that is twice as heavy will
experience the same forces due to wind resistance, but the deceleration due
to this force will be half as great. Therefore, a heavy train will slowed
less by wind drag than a light one.
What are the relative contributions of wind resistance and other dissipative
forces? Although the designers of rollercoasters must know the coefficients
of friction and drag pretty accurately for the trains they use, I don't, and
those participants in this newsgroup who do know may not be at liberty to
share that information. However, the importance of drag, and the fact that
heavier coaster trains really do go faster than light ones, is demonstrated by
the fact that cycling of "empty" trains often involves weighting them with
sandbags or water jugs. On wooden coasters with high, slow hills, an empty
train, especially one that has not been warmed up, may not be able to complete
the course.
Rastus O'Ginga
wrote:
>Hi;
>
> In short, almost all of the RE: that have been posted point to the most
>simple
>of engineering concepts...the first of which is *A little bit of knowledge
>is a dangerous thing* :o)
>The entire answer is much too complicated for K12 levels ( and most high
>schoolers that I know ).
>In short, your measurements are of total energy which are proportional to
>the mass ( weight ). The
>higher the weight, the more energyretained, the higher the train climbs (
>to a point )....this is where it gets
>complicated and where I'll end this post.
>
Uh, whatever.........
The answer is not complicated at all. Everyone knows what Potential
and Kinetic energy are (well, they should). FOr those who don't know,
Potential Energy is stored energy, while Kinetic energy is energy of
motion. You may think that the coasters start at the top of the hill
with the same zero energy. They don't. It takes more energy to raise
the heavier train to the top of the lift. You don't see that happen,
but the chain drive motor works harder.
So, the heavier coaster has more Potential energy at the top of the
hill, since it is basically mass x gravity x height. ONce both
coasters are at the bottom of the first hill, they both have zero
potential energy. So, all of the potential energy has become kinetic
energy.
Yes, the friction forces will be a bit higher on the heavy coaster,
but it is insignificant compared to the potential energy difference.
So, the heavy coaster has more momentum at the bottom of the first
hill, and will have through the entire coaster. The reason is that
there was more energy put in to that coaster train by the chain drive
on the way up the lift hill.
>Jeff
> - That's Just My Opinion, I could be Wrong -
>
>
Rastus O'Ginga
Winner of the 2nd Annual C. Montgomery Burns Award for Outstanding Achievement in the Field of Excellence.
David Keenan
bowling ball at the top of a slide. They'll both reach the bottom (barring
friction and bouncing) at the same time, but the bowling ball has so much
more of that kinetic energy than the ping-pong ball; there's no problem
with catching the ping-pong ball in your hand, but just let the bowling
ball go its merry way ;-)
Craig
> So, the heavier coaster has more Potential energy at the top of the
> hill, since it is basically mass x gravity x height. ONce both
> coasters are at the bottom of the first hill, they both have zero
> potential energy. So, all of the potential energy has become kinetic
> energy.
>
> Yes, the friction forces will be a bit higher on the heavy coaster,
> but it is insignificant compared to the potential energy difference.
> So, the heavy coaster has more momentum at the bottom of the first
> hill, and will have through the entire coaster. The reason is that
> there was more energy put in to that coaster train by the chain drive
> on the way up the lift hill.
The heavier coaster train will have higher momentum throughout the ride
because of its higher mass (momentum = mass * velocity), but technically,
its velocity at the bottom of the first drop will be the same as that of the
lighter train. What it sounds like you are overlooking is the fact that the
heavier train has higher inertia, or resitance to changes in its motion, so
it takes more energy to accelerate it.
Anytime two objects are accelerated toward the earth by gravity, they
accelerate at the same rate regardless of their mass. Mass drops out of the
equation. In reality, however, there are differences in frictional forces
that are dependent upon weight, so there may be a small difference in the
velocity of a light train vs. a heavy train. But it has nothing to do with
initial potential energy.
Justin K.
>heavier train has higher inertia, or resitance to changes in its motion, so
>it takes more energy to accelerate it.
Let's get technical. In physics, when you're dealing with collisions, momentum
is ALWAYS conserved in a closed system (ie, if you're just dealing with two
cars, with no outside input of energy). So, let's say a car and a bike are
heading directly toward each other: car has a mass of 1500 kg, the bike, 20 kg.
Both are travelling at the same velocity when they colliding. Now, what will
happen? Bike (and unfortunate rider) will be flung backwards at close to the
speed of the car, assuming the collision is elastic and no energy is lost
during the collision (which wouldn't really happen, but for sake of argument,
we say it will. This type of collision is said to be completely elastic). The
car will just slightly slow down. Air resistance is due to the collision of
the millions of air particles colliding with any surface. Just like the
bicycle with relatively small mass didn't affect the velocity of the car too
signifcantly, since car had a much greater momentum, the collisions between the
air particles and a very heavy train will affect the speed of the train less
than with collisions with a lighter train. With this reasoning, a car with a
mass of less than 1500 kg with lose more speed due to the collision with the
bicycle, since momentum is always conserved.
If any of you are still following me, and wish to critique, etc, what I've
said, feel free :)
BGTG...@aol.com (remove "ToTRules" to reply)
***************************
<a href="http://members.tripod.com/jkdesigns/intro.htm">JK Designs</a>.
Take a look!
Rastus O'Ginga
>Rastus wrote:
>
>> So, the heavier coaster has more Potential energy at the top of the
>> hill, since it is basically mass x gravity x height. ONce both
>> coasters are at the bottom of the first hill, they both have zero
>> potential energy. So, all of the potential energy has become kinetic
>> energy.
>>
>> Yes, the friction forces will be a bit higher on the heavy coaster,
>> but it is insignificant compared to the potential energy difference.
>> So, the heavy coaster has more momentum at the bottom of the first
>> hill, and will have through the entire coaster. The reason is that
>> there was more energy put in to that coaster train by the chain drive
>> on the way up the lift hill.
>
>The heavier coaster train will have higher momentum throughout the ride
>because of its higher mass (momentum = mass * velocity), but technically,
>its velocity at the bottom of the first drop will be the same as that of the
>lighter train. What it sounds like you are overlooking is the fact that the
>heavier train has higher inertia, or resitance to changes in its motion, so
>it takes more energy to accelerate it.
>
>Anytime two objects are accelerated toward the earth by gravity, they
>accelerate at the same rate regardless of their mass. Mass drops out of the
>equation. In reality, however, there are differences in frictional forces
>that are dependent upon weight, so there may be a small difference in the
>velocity of a light train vs. a heavy train. But it has nothing to do with
>initial potential energy.
>
>
It has EVERYTHING to do with the initial potential energy. That is
the only time that the mass matters. You are just trying to
overcomplicate it and sound smart by bringing in the momentum and
inertia. Those two are different properties that again boil down to
kinetic energy. Trust me, the ONLY differences in a heavy and light
coaster train are frictional forces, which are relatively negligable,
and the initial potential energy. Everything else is needless
complications.
You should probably get an engineering degree before you start saying
that is has nothing to do with the initial potential energy. At least
take a HS Physics class or something.
Rastus O'Ginga
wrote:
>>What it sounds like you are overlooking is the fact that the
>>heavier train has higher inertia, or resitance to changes in its motion, so
>>it takes more energy to accelerate it.
>
>Let's get technical. In physics, when you're dealing with collisions, momentum
>is ALWAYS conserved in a closed system (ie, if you're just dealing with two
>cars, with no outside input of energy). So, let's say a car and a bike are
>heading directly toward each other: car has a mass of 1500 kg, the bike, 20 kg.
> Both are travelling at the same velocity when they colliding. Now, what will
>happen? Bike (and unfortunate rider) will be flung backwards at close to the
>speed of the car, assuming the collision is elastic and no energy is lost
>during the collision (which wouldn't really happen, but for sake of argument,
>we say it will. This type of collision is said to be completely elastic). The
>car will just slightly slow down. Air resistance is due to the collision of
>the millions of air particles colliding with any surface. Just like the
>bicycle with relatively small mass didn't affect the velocity of the car too
>signifcantly, since car had a much greater momentum, the collisions between the
>air particles and a very heavy train will affect the speed of the train less
>than with collisions with a lighter train. With this reasoning, a car with a
>mass of less than 1500 kg with lose more speed due to the collision with the
>bicycle, since momentum is always conserved.
>
>If any of you are still following me, and wish to critique, etc, what I've
>said, feel free :)
>
This is still waaaay too much complication. It comes down to the
initial potential energy the train has at the top of the first lift
hill and that is IT. The chain puts just enough energy into the train
to get it to the top of the hill. Once the train starts down the
hill, potential energy turns to kinetic energy (momentum, inertia,
whatever). The amount of TOTAL energy it has will never be more than
it's initial potential energy at the top of the hill, plus its very
slight kinetic energy of a few mph.
From that point on, frictional forces slowly eat up the energy of the
train and turn it to heat. These frictional forces are going to be a
bit higher on the heavier train, but not enough to make the heavier
train ever have less energy than the lighter train at any given point
on the track layout. Thus, the heavier train will traverse the track
faster than the lighter train, except for extreme circumstances.
>BGTG...@aol.com (remove "ToTRules" to reply)
>***************************
><a href="http://members.tripod.com/jkdesigns/intro.htm">JK Designs</a>.
>Take a look!
Dave Sandborg
<ras...@insync.net> wrote:
> On Sat, 12 Feb 2000 20:10:40 GMT, "Craig" <nos...@excite.com> wrote:
>
> >Anytime two objects are accelerated toward the earth by gravity, they
> >accelerate at the same rate regardless of their mass. Mass drops out of the
> >equation. In reality, however, there are differences in frictional forces
> >that are dependent upon weight, so there may be a small difference in the
> >velocity of a light train vs. a heavy train. But it has nothing to do with
> >initial potential energy.
> >
> >
>
> It has EVERYTHING to do with the initial potential energy.
I'd agree and disagree with both of you. It certainly does not have
*nothing* to do with potential energy, but the rest of Craig's explanation
is basically cogent, and cleaner than any based on energy that I can see.
Energy is important, but it doesn't seem to provide as good a basis for an
explanation here. You can't get much simpler than saying that mass cancels
out of all equations except those involving air resistance (as somebody
else mentioned, it's really air resistance, not friction that matters
here), hence a more massive train travels faster. Simple, but correct, and
energy doesn't get mentioned. I understand the utility of energy in roller
coaster physics (I use it a lot in the physics page I wrote for
Rollercoaster.com and the CEC page), but it doesn't seem to do as well here
as an explanation here.
Rastus O'Ginga
wrote:
>Rastus O'Ginga <ras...@insync.net> wrote:
>
>> It has EVERYTHING to do with the initial potential energy. That is
>> the only time that the mass matters. You are just trying to
>> overcomplicate it and sound smart by bringing in the momentum and
>> inertia. Those two are different properties that again boil down to
>> kinetic energy. Trust me, the ONLY differences in a heavy and light
>> coaster train are frictional forces, which are relatively negligable,
>> and the initial potential energy. Everything else is needless
>> complications.
>
>Wrong. The difference in speed between a heavy and light train is due
>*solely* to the difference in frictional forces, and it has *nothing* to do
>with the difference in initial potential energy. If you could eliminate
>the frictional forces, then the heavy and light train would go exactly the
>same speed, *regardless* of their difference in initial potential energy.
I suggest you choose your fights with me, and this is one should NOT
choose. Yes, both objects will FALL at the same speed in a vacuum.
Yes, both objects FALL at the same speed, except for different
frictional effects from air resistance. BUT, when the trains are at
the bottom of the first hill, and are NOT falling anymore, the heavier
train has more kinetic energy from the fall, and thus will travel
faster through the course. THe effect of gravity (acceleration) is
the same on both. The potential energy gained by both while going up
the lift hill is TOTALLY dependent on weight.
>
>As Dave Althoff has already explained earlier in this thread, some
>frictional forces (such as the rolling resistance of the wheels) will vary
>with the mass of the train, and other frictional forces (such as air
>resistance) will *not* vary with the mass of the train. It's the latter
>type of frictional force that causes a lighter train to go slower than a
>heavier train.
Dave was right in what he said, but it all boils down to INITIAL
POTENTIAL ENERGY!!!!!! The frictional forces eat up the energy that
the train has. The only place a train gains energy is in the lift
hill. I am NOT wrong on this. How many college level physics and
thermodynamics courses have you taken? I took three and got an A and
2 B's. IF you want to argue this more, go right ahead.
I wouldn't be this pompus, but you are the one saying I was wrong.
Science is nothing but FACTS, unlike politics and gay rights there is
only ONE correct answer.
>
>------------------------------------------------------------------
>Joe Schwartz (j...@joyrides.com) -- 5 Broadway #407, Troy, NY 12180
>
> Come visit the Joyrides website <http://www.joyrides.com>,
>a photo gallery celebrating the joy and beauty of amusement rides!
Rastus O'Ginga
(Dave Sandborg) wrote:
>In article <1u5casolujqu3ism6...@4ax.com>, Rastus O'Ginga
><ras...@insync.net> wrote:
>
>> On Sat, 12 Feb 2000 20:10:40 GMT, "Craig" <nos...@excite.com> wrote:
>>
>> >Anytime two objects are accelerated toward the earth by gravity, they
>> >accelerate at the same rate regardless of their mass. Mass drops out of the
>> >equation. In reality, however, there are differences in frictional forces
>> >that are dependent upon weight, so there may be a small difference in the
>> >velocity of a light train vs. a heavy train. But it has nothing to do with
>> >initial potential energy.
>> >
>> >
>>
>> It has EVERYTHING to do with the initial potential energy.
>
>I'd agree and disagree with both of you. It certainly does not have
>*nothing* to do with potential energy, but the rest of Craig's explanation
>is basically cogent, and cleaner than any based on energy that I can see.
>Energy is important, but it doesn't seem to provide as good a basis for an
>explanation here. You can't get much simpler than saying that mass cancels
>out of all equations except those involving air resistance (as somebody
>else mentioned, it's really air resistance, not friction that matters
>here),
Air resistance IS a frictional force. That's simply splittting hairs.
hence a more massive train travels faster. Simple, but correct, and
>energy doesn't get mentioned. I understand the utility of energy in roller
>coaster physics (I use it a lot in the physics page I wrote for
>Rollercoaster.com and the CEC page), but it doesn't seem to do as well here
>as an explanation here.
Joe Schwartz
> It has EVERYTHING to do with the initial potential energy. That is
> the only time that the mass matters. You are just trying to
> overcomplicate it and sound smart by bringing in the momentum and
> inertia. Those two are different properties that again boil down to
> kinetic energy. Trust me, the ONLY differences in a heavy and light
> coaster train are frictional forces, which are relatively negligable,
> and the initial potential energy. Everything else is needless
> complications.
Wrong. The difference in speed between a heavy and light train is due
*solely* to the difference in frictional forces, and it has *nothing* to do
with the difference in initial potential energy. If you could eliminate
the frictional forces, then the heavy and light train would go exactly the
same speed, *regardless* of their difference in initial potential energy.
As Dave Althoff has already explained earlier in this thread, some
frictional forces (such as the rolling resistance of the wheels) will vary
with the mass of the train, and other frictional forces (such as air
resistance) will *not* vary with the mass of the train. It's the latter
type of frictional force that causes a lighter train to go slower than a
heavier train.
------------------------------------------------------------------
Joe Schwartz
> Rastus O'Ginga <ras...@insync.net> wrote:
>
> > It has EVERYTHING to do with the initial potential energy. That is
> > the only time that the mass matters. You are just trying to
> > overcomplicate it and sound smart by bringing in the momentum and
> > inertia. Those two are different properties that again boil down to
> > kinetic energy. Trust me, the ONLY differences in a heavy and light
> > coaster train are frictional forces, which are relatively negligable,
> > and the initial potential energy. Everything else is needless
> > complications.
>
> Wrong. The difference in speed between a heavy and light train is due
> *solely* to the difference in frictional forces, and it has *nothing* to do
> with the difference in initial potential energy. If you could eliminate
> the frictional forces, then the heavy and light train would go exactly the
> same speed, *regardless* of their difference in initial potential energy.
Let me clarify this. The difference in potential energy wouldn't affect
the speed, because that difference is exactly proportional to the mass of
the trains (U = mgh). If the heavier train had twice as much mass as the
lighter train, it would have twice the potential energy, and twice the
kinetic energy, but since K = 1/2 * mv^2, it takes twice as much kinetic
energy to move the heavier train at the same velocity as the lighter train.
If you set K = U (kinetic energy at the bottom equals potential energy at
the top), then you have mgh = 1/2 * mv^2, and mass drops out. The
resulting velocity v = sqrt(2gh) is independent of mass.
Craig
>Just like the
> bicycle with relatively small mass didn't affect the velocity of the car
too
> signifcantly, since car had a much greater momentum, the collisions
between the
> air particles and a very heavy train will affect the speed of the train
less
> than with collisions with a lighter train. With this reasoning, a car
with a
> mass of less than 1500 kg with lose more speed due to the collision with
the
> bicycle, since momentum is always conserved.
I think that what you are saying is basically correct. Air drag creates a
force on the train that is opposite the direction of motion. The lighter
train will decelerate at a faster rate than the heavy train as a result of
this force. That makes sense. The interesting thing is that the air drag
coefficient is a function of the geometry of the train which means that we
could begin to ask the question: does a train with lots of tall people slow
down more quickly than a train full of short people because it has a higher
drag coefficient? Hmmmm.
Joe Schwartz
> I suggest you choose your fights with me, and this is one should NOT
> choose.
Ha.
> Yes, both objects will FALL at the same speed in a vacuum.
> Yes, both objects FALL at the same speed, except for different
> frictional effects from air resistance. BUT, when the trains are at
> the bottom of the first hill, and are NOT falling anymore, the heavier
> train has more kinetic energy from the fall, and thus will travel
> faster through the course.
Yes, the heavier train has more kinetic energy from the fall. However, the
added kinetic energy does *not* cause it to travel faster throughout the
course. The train's velocity depends on its mass as well as its kinetic
energy, and the two differences cancel each other out.
> THe effect of gravity (acceleration) is the same on both. The potential
> energy gained by both while going up the lift hill is TOTALLY dependent on
> weight.
Correct. But the velocity is not affected.
> Dave was right in what he said, but it all boils down to INITIAL
> POTENTIAL ENERGY!!!!!! The frictional forces eat up the energy that
> the train has. The only place a train gains energy is in the lift
> hill. I am NOT wrong on this.
I never said you were wrong on that. The energy levels of the two trains
*are* different, just as you said. But their velocities are equal (or
rather, they would be equal if not for friction).
> How many college level physics and thermodynamics courses have you
> taken? I took three and got an A and 2 B's.
I took three and got three A's. My three-of-a-kind beats your pair.
> I wouldn't be this pompus, but you are the one saying I was wrong.
> Science is nothing but FACTS, unlike politics and gay rights there is
> only ONE correct answer.
I agree. The correct answer is mine. Check your facts.
Dave Sandborg
<ras...@insync.net> wrote:
> On Sun, 13 Feb 2000 03:53:23 GMT, Joe Schwartz <j...@joyrides.com>
> wrote:
> >
> >Wrong. The difference in speed between a heavy and light train is due
> >*solely* to the difference in frictional forces, and it has *nothing* to do
> >with the difference in initial potential energy. If you could eliminate
> >the frictional forces, then the heavy and light train would go exactly the
> >same speed, *regardless* of their difference in initial potential energy.
>
> I suggest you choose your fights with me, and this is one should NOT
> choose. Yes, both objects will FALL at the same speed in a vacuum.
> Yes, both objects FALL at the same speed, except for different
> frictional effects from air resistance. BUT, when the trains are at
> the bottom of the first hill, and are NOT falling anymore, the heavier
> train has more kinetic energy from the fall, and thus will travel
> faster through the course. THe effect of gravity (acceleration) is
> the same on both. The potential energy gained by both while going up
> the lift hill is TOTALLY dependent on weight.
I'm honestly not sure what your basic claim is, but if you're saying that a
heavier train would travel faster through the course than a lighter if
there were no resistive forces (not splitting hairs w/r/t friction this
time), then Joe is right and you are wrong. In fact you should know this,
as a very simple energy argument proves it.
Craig
> It has EVERYTHING to do with the initial potential energy.
When you say that "it has EVERYTHING to do with the initial potential
energy," what exactly do you mean by "it?" If by "it" you are refering to
the difference in speed of a ligh train versus a heavy train, I would
disagree. The iniitial potential energy has nothing to do with the
difference in the speeds of the train because gravity accelerates each train
at the same rate, regardless of its mass. The difference is the train
speeds can be accounted for by the differences in energy losses which may be
functions of the train masses.
Let me phrase it differently: If it were possible to remove all energy
losses, the light train and the heavy train would travel the circuit at
exactly the same speed even though the heavy one has a higher initial
potential energy.
>You are just trying to overcomplicate it and sound smart by bringing in the
momentum and
> inertia.
Huh? Trying to sound smart? No, not at all. Momentum and inertia are
pretty simple concepts. This is high school stuff.
>Those two are different properties that again boil down to
> kinetic energy. Trust me, the ONLY differences in a heavy and light
> coaster train are frictional forces, which are relatively negligable,
> and the initial potential energy. Everything else is needless
> complications.
I agree that energy losses may be a function of train mass. I also agree
that initial potential energy is a funtion of train mass. All that I am
saying is that the difference in speeds of the light and heavy trains cannot
be accounted for by the difference in their initial potential energies.
When gravitational potential energy is converted to kinetic energy of
motion, it is done so independently of mass. All differences in speed are
attributed to differences in energy losses.
> You should probably get an engineering degree before you start saying
> that is has nothing to do with the initial potential energy. At least
> take a HS Physics class or something.
I have a master's degree in mechanical engineering from Ohio State. But it
doesn't mean a thing. This is high school stuff.
> Rastus O'Ginga
>
> Winner of the 2nd Annual C. Montgomery Burns Award for Outstanding
Achievement in the Field of >Excellence.
That's nice.
Dj Detonator
wrote:
>> How many college level physics and thermodynamics courses have you
>> taken? I took three and got an A and 2 B's.
>
>I took three and got three A's. My three-of-a-kind beats your pair.
>
>> I wouldn't be this pompus, but you are the one saying I was wrong.
>> Science is nothing but FACTS, unlike politics and gay rights there is
>> only ONE correct answer.
>
>I agree. The correct answer is mine. Check your facts.
/user stands up behind Joe and hollers "Yeah, bitch!" at Rastus
Rastus O'Ginga
wrote:
>I wrote:
>
>> Rastus O'Ginga <ras...@insync.net> wrote:
>>
>> > It has EVERYTHING to do with the initial potential energy. That is
>> > the only time that the mass matters. You are just trying to
>> > overcomplicate it and sound smart by bringing in the momentum and
>> > inertia. Those two are different properties that again boil down to
>> > kinetic energy. Trust me, the ONLY differences in a heavy and light
>> > coaster train are frictional forces, which are relatively negligable,
>> > and the initial potential energy. Everything else is needless
>> > complications.
>>
>> Wrong. The difference in speed between a heavy and light train is due
>> *solely* to the difference in frictional forces, and it has *nothing* to do
>> with the difference in initial potential energy. If you could eliminate
>> the frictional forces, then the heavy and light train would go exactly the
>> same speed, *regardless* of their difference in initial potential energy.
>
>Let me clarify this. The difference in potential energy wouldn't affect
>the speed, because that difference is exactly proportional to the mass of
>the trains (U = mgh). If the heavier train had twice as much mass as the
>lighter train, it would have twice the potential energy, and twice the
>kinetic energy, but since K = 1/2 * mv^2, it takes twice as much kinetic
>energy to move the heavier train at the same velocity as the lighter train.
>If you set K = U (kinetic energy at the bottom equals potential energy at
>the top), then you have mgh = 1/2 * mv^2, and mass drops out. The
>resulting velocity v = sqrt(2gh) is independent of mass.
>
Yes, the VELOCITY is independent of mass in a vacuum. That goes back
to the old experiment of dropping a feather and a brick in a vacuum.
But that is still not the point here. As I said, the only thing that
takes away Energy is friction. Friction is the friction of the wheels
with the track and wind resistance. As everyone has said, the wind
resistance is pretty much constant, regardless of the weight of the
trains. The track friction is a bit larger on the heavier train
though. So, the heavier train loses are perhaps a larger amount of
energy going down the first hill, but as a percentage, it loses less
than the lighter train, so it really will go faster at the bottom of
the lift hill. Again, because it had more energy to begin with.
This is why, on a cold day, many parks require the trains to be full.
The frictional losses are greater in the cold since the grease is more
viscous. But, filling the train and therefore giving it more energy
from the lift hill, gives it more energy through the rest of the ride.
All other things being basically constant.
If what you are trying to say was true, there would be absolutely no
reason for parks to test trains full of water dummies. Yet, they all
do it.
>------------------------------------------------------------------
>Joe Schwartz (j...@joyrides.com) -- 5 Broadway #407, Troy, NY 12180
>
> Come visit the Joyrides website <http://www.joyrides.com>,
>a photo gallery celebrating the joy and beauty of amusement rides!
Rastus O'Ginga
wrote:
>Rastus O'Ginga <ras...@insync.net> wrote:
>
>> I suggest you choose your fights with me, and this is one should NOT
>> choose.
>
>Ha.
>
>> Yes, both objects will FALL at the same speed in a vacuum.
>> Yes, both objects FALL at the same speed, except for different
>> frictional effects from air resistance. BUT, when the trains are at
>> the bottom of the first hill, and are NOT falling anymore, the heavier
>> train has more kinetic energy from the fall, and thus will travel
>> faster through the course.
>
>Yes, the heavier train has more kinetic energy from the fall. However, the
>added kinetic energy does *not* cause it to travel faster throughout the
>course. The train's velocity depends on its mass as well as its kinetic
>energy, and the two differences cancel each other out.
>
>> THe effect of gravity (acceleration) is the same on both. The potential
>> energy gained by both while going up the lift hill is TOTALLY dependent on
>> weight.
>
>Correct. But the velocity is not affected.
>
>> Dave was right in what he said, but it all boils down to INITIAL
>> POTENTIAL ENERGY!!!!!! The frictional forces eat up the energy that
>> the train has. The only place a train gains energy is in the lift
>> hill. I am NOT wrong on this.
>
>I never said you were wrong on that. The energy levels of the two trains
>*are* different, just as you said. But their velocities are equal (or
>rather, they would be equal if not for friction).
Your parenthetical statement is the key. See my other post for the
explanation.
>
>> How many college level physics and thermodynamics courses have you
>> taken? I took three and got an A and 2 B's.
>
>I took three and got three A's. My three-of-a-kind beats your pair.
>
Actually depends on the University, but that's a whole other story.
>> I wouldn't be this pompus, but you are the one saying I was wrong.
>> Science is nothing but FACTS, unlike politics and gay rights there is
>> only ONE correct answer.
>
>I agree. The correct answer is mine. Check your facts.
>
Rastus O'Ginga
Detonator) wrote:
>On Sun, 13 Feb 2000 05:02:15 GMT, Joe Schwartz <j...@joyrides.com>
>wrote:
>
>>> How many college level physics and thermodynamics courses have you
>>> taken? I took three and got an A and 2 B's.
>>
>>I took three and got three A's. My three-of-a-kind beats your pair.
>>
>>> I wouldn't be this pompus, but you are the one saying I was wrong.
>>> Science is nothing but FACTS, unlike politics and gay rights there is
>>> only ONE correct answer.
>>
>>I agree. The correct answer is mine. Check your facts.
>
>/user stands up behind Joe and hollers "Yeah, bitch!" at Rastus
How pathetic that you even stand behind other people in an anonymous
news forum.
Rastus O'Ginga
>Rastus wrote:
>
>> It has EVERYTHING to do with the initial potential energy.
>
>When you say that "it has EVERYTHING to do with the initial potential
>energy," what exactly do you mean by "it?" If by "it" you are refering to
>the difference in speed of a ligh train versus a heavy train, I would
>disagree. The iniitial potential energy has nothing to do with the
>difference in the speeds of the train because gravity accelerates each train
>at the same rate, regardless of its mass. The difference is the train
>speeds can be accounted for by the differences in energy losses which may be
>functions of the train masses.
>
The energy losses are just that, losses. But, since the heavier train
has more energy to begin with, once it has those losses, it still has
more energy left than the light train. See other posts for a in-depth
explanation.
>Let me phrase it differently: If it were possible to remove all energy
>losses, the light train and the heavy train would travel the circuit at
>exactly the same speed even though the heavy one has a higher initial
>potential energy.
But, that's not the world we live in.
>
>>You are just trying to overcomplicate it and sound smart by bringing in the
>momentum and
>> inertia.
>
>Huh? Trying to sound smart? No, not at all. Momentum and inertia are
>pretty simple concepts. This is high school stuff.
>
>>Those two are different properties that again boil down to
>> kinetic energy. Trust me, the ONLY differences in a heavy and light
>> coaster train are frictional forces, which are relatively negligable,
>> and the initial potential energy. Everything else is needless
>> complications.
>
>I agree that energy losses may be a function of train mass. I also agree
>that initial potential energy is a funtion of train mass. All that I am
>saying is that the difference in speeds of the light and heavy trains cannot
>be accounted for by the difference in their initial potential energies.
>When gravitational potential energy is converted to kinetic energy of
>motion, it is done so independently of mass. All differences in speed are
>attributed to differences in energy losses.
RIght, and those energy losses are very mass-independent. So, the
heavier train losses a smaller percentage of its energy, and thus
travels faster through the course. I still don't understand the
argument here. Why do you think parks require full trains on cold
days?
>
>> You should probably get an engineering degree before you start saying
>> that is has nothing to do with the initial potential energy. At least
>> take a HS Physics class or something.
>
>I have a master's degree in mechanical engineering from Ohio State. But it
>doesn't mean a thing. This is high school stuff.
>
Well, you're right there, it is something you should have learned in
high school (as I stated). The reason I bring up classes is because
of the fact that everyone always wants to argue my posts, yet in this
case there is no argument. Science is not an art.
As far as my pedigree, I have a BS in Chemical Engineering from
Purdue. My point being that I am qualified to make these statements,
regardless of if you agree with my political opinions.
>> Rastus O'Ginga
>>
>> Winner of the 2nd Annual C. Montgomery Burns Award for Outstanding
>Achievement in the Field of >Excellence.
>
>That's nice.
Rastus O'Ginga
(Dave Sandborg) wrote:
>In article <uadcas480ju9uo3n4...@4ax.com>, Rastus O'Ginga
><ras...@insync.net> wrote:
>
>> On Sun, 13 Feb 2000 03:53:23 GMT, Joe Schwartz <j...@joyrides.com>
>> wrote:
>> >
>> >Wrong. The difference in speed between a heavy and light train is due
>> >*solely* to the difference in frictional forces, and it has *nothing* to do
>> >with the difference in initial potential energy. If you could eliminate
>> >the frictional forces, then the heavy and light train would go exactly the
>> >same speed, *regardless* of their difference in initial potential energy.
>>
>> I suggest you choose your fights with me, and this is one should NOT
>> choose. Yes, both objects will FALL at the same speed in a vacuum.
>> Yes, both objects FALL at the same speed, except for different
>> frictional effects from air resistance. BUT, when the trains are at
>> the bottom of the first hill, and are NOT falling anymore, the heavier
>> train has more kinetic energy from the fall, and thus will travel
>> faster through the course. THe effect of gravity (acceleration) is
>> the same on both. The potential energy gained by both while going up
>> the lift hill is TOTALLY dependent on weight.
>
>I'm honestly not sure what your basic claim is, but if you're saying that a
>heavier train would travel faster through the course than a lighter if
>there were no resistive forces (not splitting hairs w/r/t friction this
>time), then Joe is right and you are wrong. In fact you should know this,
>as a very simple energy argument proves it.
I'm not talking about a case with no resistive forces. That's not the
world in which coasters operate.
Joe Schwartz
> Yes, the VELOCITY is independent of mass in a vacuum. That goes back
> to the old experiment of dropping a feather and a brick in a vacuum.
> But that is still not the point here.
Let's take a moment to review the argument. The point here (referring to
the Subject line) is whether heavier cars/trains go faster than lighter
cars/trains, and why. Originally, you said this:
> It has EVERYTHING to do with the initial potential energy. That is
> the only time that the mass matters. You are just trying to
> overcomplicate it and sound smart by bringing in the momentum and
> inertia. Those two are different properties that again boil down to
> kinetic energy. Trust me, the ONLY differences in a heavy and light
> coaster train are frictional forces, which are relatively negligable,
> and the initial potential energy. Everything else is needless
> complications.
My complaint was that you said the frictional forces are "relatively
negligable". In fact, they are not negligable -- they are the *only* cause
of the difference in velocity between a heavy train and a light train. I
responded with this:
> Wrong. The difference in speed between a heavy and light train is due
> *solely* to the difference in frictional forces, and it has *nothing* to do
> with the difference in initial potential energy. If you could eliminate
> the frictional forces, then the heavy and light train would go exactly the
> same speed, *regardless* of their difference in initial potential energy.
It's clear that you agree with my last sentence above, but apparently you
think that's not the point here. You continued:
> As I said, the only thing that takes away Energy is friction. Friction
> is the friction of the wheels with the track and wind resistance.
Yep, you got that right.
> As everyone has said, the wind resistance is pretty much constant,
> regardless of the weight of the trains. The track friction is a bit
> larger on the heavier train though. So, the heavier train loses are
> perhaps a larger amount of energy going down the first hill, but as a
> percentage, it loses less than the lighter train, so it really will go
> faster at the bottom of the lift hill.
Correct again.
> Again, because it had more energy to begin with.
Nope, here's where you keep getting it wrong. The heavier train does not
go faster because it has more energy than the lighter train -- it goes
faster because its loss of energy is not proportional to its mass.
What you fail to understand is that increasing a train's energy does *not*
increase its velocity, when you also increase its mass by the same amount.
Even if both trains were going the same speed, the heavier train would have
more energy. In fact, the heavier train could go slighter *slower* than
the lighter train and still have more energy.
> This is why, on a cold day, many parks require the trains to be full.
> The frictional losses are greater in the cold since the grease is more
> viscous. But, filling the train and therefore giving it more energy
> from the lift hill, gives it more energy through the rest of the ride.
> All other things being basically constant.
>
> If what you are trying to say was true, there would be absolutely no
> reason for parks to test trains full of water dummies. Yet, they all
> do it.
I'm not the one saying that frictional forces are unimportant -- you're the
one who called them "relatively negligable" and insisted that the
difference in potential energy is more important. To illustrate how
important the frictional forces actually are in affecting the speed, I
simply pointed out that without them, a heavy train would go just as fast
as a light train. I never said that frictional forces don't exist.
In any case, you've proved my point that frictional forces cause heavier
trains to go faster than lighter trains. Thank you.
Joe Schwartz
> On Sun, 13 Feb 2000 05:02:15 GMT, Joe Schwartz <j...@joyrides.com>
> wrote:
>
> >I never said you were wrong on that. The energy levels of the two trains
> >*are* different, just as you said. But their velocities are equal (or
> >rather, they would be equal if not for friction).
>
> Your parenthetical statement is the key. See my other post for the
> explanation.
Yes, my parenthetical statement is the key. As I originally said, friction
is the *only* reason why a heavy train goes faster than a light train.
> >> How many college level physics and thermodynamics courses have you
> >> taken? I took three and got an A and 2 B's.
> >
> >I took three and got three A's. My three-of-a-kind beats your pair.
>
> Actually depends on the University, but that's a whole other story.
My three A's were from Rensselaer Polytechnic Institute, as were my B.S.
and my 4.0 GPA. Please feel free to share your credentials.
Justin K.
>initial potential energy the train has at the top of the first lift
>hill and that is IT.
That's not IT... What if there were a massive plexiglass shield attached to the
front of the train? High potential energy or not, this train will experience a
LOT of drag force, and might just go more slowly at the bottom of the hill than
a lighter train. Drag forces have NOTHING to do with potential energy. In
fact, the resistive force is given by the equation F = bv, where b is a
constant, determined essentially by the mass and shape of the object. No
potential energy here. For a heavy, aerodynamically designed train, b is
relatively small compared to a light, non-aerodynamically designed train.
Therefore, for high speeds, the first train mentioned will experience less
dissipative force than the second train. And while yes, it does have to do
with potential and kinetic energy, as I've explained above, energy is most
definitely NOT the ONLY argument.
Dave Sandborg
<ras...@insync.net> wrote:
> On Sun, 13 Feb 2000 00:21:48 -0500, sand...@Spam-away.ix.netcom.com
> (Dave Sandborg) wrote:
>
> >In article <uadcas480ju9uo3n4...@4ax.com>, Rastus O'Ginga
> ><ras...@insync.net> wrote:
> >
> >> On Sun, 13 Feb 2000 03:53:23 GMT, Joe Schwartz <j...@joyrides.com>
> >> wrote:
> >> >
> >> >Wrong. The difference in speed between a heavy and light train is due
> >> >*solely* to the difference in frictional forces, and it has *nothing*
to do
> >> >with the difference in initial potential energy. If you could eliminate
> >> >the frictional forces, then the heavy and light train would go exactly the
> >> >same speed, *regardless* of their difference in initial potential energy.
> >>
> >> I suggest you choose your fights with me, and this is one should NOT
> >> choose. Yes, both objects will FALL at the same speed in a vacuum.
> >> Yes, both objects FALL at the same speed, except for different
> >> frictional effects from air resistance. BUT, when the trains are at
> >> the bottom of the first hill, and are NOT falling anymore, the heavier
> >> train has more kinetic energy from the fall, and thus will travel
> >> faster through the course. THe effect of gravity (acceleration) is
> >> the same on both. The potential energy gained by both while going up
> >> the lift hill is TOTALLY dependent on weight.
> >
> >I'm honestly not sure what your basic claim is, but if you're saying that a
> >heavier train would travel faster through the course than a lighter if
> >there were no resistive forces (not splitting hairs w/r/t friction this
> >time), then Joe is right and you are wrong. In fact you should know this,
> >as a very simple energy argument proves it.
>
> I'm not talking about a case with no resistive forces. That's not the
> world in which coasters operate.
Fine, then you should express yourself more clearly. You should also seek
to understand Joe's arguments better. What Joe says in the text with four
carets above is precisely correct. You disagreed, without being very clear
what the point of disagreement was. What is the point of the statement,
"...when the trains are at the bottom of the first hill, and are NOT
falling anymore...[etc.]"? This makes makes it sound as if you're saying
that it's *merely* because the train is no longer freely falling that there
are differences in speed from that point on. But that's certainly not
true; there are forces besides gravity operating on the train that do not
diminish its energy.
I did what I could in regard to interpreting your argument, but I wasn't
sure...hence the hedge words in my own response. Since you deny my
reconstruction of your argument, I'm *still* in the dark about what your
actual disagreement with Joe is. I suspect you simply misunderstand his
argument. In another post, you say "If what you [Joe] are trying to say
was true, there would be absolutely no reason for parks to test trains full
of water dummies. Yet, they all do it." The second sentence is true, but
the first is false. Joe makes no such claim, and his argument by no means
implies it.
Rastus O'Ginga
wrote:
>>This is still waaaay too much complication. It comes down to the
>>initial potential energy the train has at the top of the first lift
>>hill and that is IT.
>
>That's not IT... What if there were a massive plexiglass shield attached to the
>front of the train? High potential energy or not, this train will experience a
>LOT of drag force, and might just go more slowly at the bottom of the hill than
>a lighter train. Drag forces have NOTHING to do with potential energy. In
>fact, the resistive force is given by the equation F = bv, where b is a
>constant, determined essentially by the mass and shape of the object. No
>potential energy here. For a heavy, aerodynamically designed train, b is
>relatively small compared to a light, non-aerodynamically designed train.
>Therefore, for high speeds, the first train mentioned will experience less
>dissipative force than the second train. And while yes, it does have to do
>with potential and kinetic energy, as I've explained above, energy is most
>definitely NOT the ONLY argument.
>
Energy is everything. The train gets energy on the hill, and loses it
to friction throughout the ride. The friction losses are reletively
equal, but the initial P energy is more for the heavy train.
Everything else is just splitting hairs.
>BGTG...@aol.com (remove "ToTRules" to reply)
>***************************
><a href="http://members.tripod.com/jkdesigns/intro.htm">JK Designs</a>.
>Take a look!
Rastus O'Ginga
wrote:
>Rastus O'Ginga <ras...@insync.net> wrote:
>
>> On Sun, 13 Feb 2000 05:02:15 GMT, Joe Schwartz <j...@joyrides.com>
>> wrote:
>>
>> >I never said you were wrong on that. The energy levels of the two trains
>> >*are* different, just as you said. But their velocities are equal (or
>> >rather, they would be equal if not for friction).
>>
>> Your parenthetical statement is the key. See my other post for the
>> explanation.
>
>Yes, my parenthetical statement is the key. As I originally said, friction
>is the *only* reason why a heavy train goes faster than a light train.
>
>> >> How many college level physics and thermodynamics courses have you
>> >> taken? I took three and got an A and 2 B's.
>> >
>> >I took three and got three A's. My three-of-a-kind beats your pair.
>>
>> Actually depends on the University, but that's a whole other story.
>
>My three A's were from Rensselaer Polytechnic Institute, as were my B.S.
>and my 4.0 GPA. Please feel free to share your credentials.
>
Well, my 3 semester A's were at Purdue University. I said that not to
start a "my university is better than yours" argument, but simply to
show that I do have the background for this argument. Like I said,
this is science, there is but one true answer. It's not like all the
other arguments where there is not necessarily a correct answer, and
all opinions matter. If you don't have the background, you shouldn't
enter it. And to bluntly say someone is wrong, is a very ballsy thing
to do.
Actually I've argued the RPI vs Purdue thing before (engineering that
is). RPI is similar to many other small schools. Locally everyone
praises it, and this gives the alumni big heads. Nationally, however,
they are relatively unknown, similar to Rose Hulman (a very similar
expensive private school in Indiana that you probably have never heard
of).
Pure grades come down to how hard you study for them, and what level
of class you took.. That is to say the engineers at Purdue took much
more difficult Physics courses than other-majored students.
I usually use the Engineer in Training test as a true guide. I passed
it, and would consider all others who passed it to have similar
engineering abilities as I do, regardless of the school they went to.
>------------------------------------------------------------------
>Joe Schwartz (j...@joyrides.com) -- 5 Broadway #407, Troy, NY 12180
>
> Come visit the Joyrides website <http://www.joyrides.com>,
>a photo gallery celebrating the joy and beauty of amusement rides!
Rastus O'Ginga
wrote:
>Rastus O'Ginga <ras...@insync.net> wrote:
>
>> Yes, the VELOCITY is independent of mass in a vacuum. That goes back
>> to the old experiment of dropping a feather and a brick in a vacuum.
>> But that is still not the point here.
>
>Let's take a moment to review the argument. The point here (referring to
>the Subject line) is whether heavier cars/trains go faster than lighter
>cars/trains, and why. Originally, you said this:
>
>> It has EVERYTHING to do with the initial potential energy. That is
>> the only time that the mass matters. You are just trying to
>> overcomplicate it and sound smart by bringing in the momentum and
>> inertia. Those two are different properties that again boil down to
>> kinetic energy. Trust me, the ONLY differences in a heavy and light
>> coaster train are frictional forces, which are relatively negligable,
>> and the initial potential energy. Everything else is needless
>> complications.
>
>My complaint was that you said the frictional forces are "relatively
>negligable". In fact, they are not negligable -- they are the *only* cause
>of the difference in velocity between a heavy train and a light train. I
>responded with this:
>
>> Wrong. The difference in speed between a heavy and light train is due
>> *solely* to the difference in frictional forces, and it has *nothing* to do
>> with the difference in initial potential energy. If you could eliminate
>> the frictional forces, then the heavy and light train would go exactly the
>> same speed, *regardless* of their difference in initial potential energy.
>
>> If what you are trying to say was true, there would be absolutely no
>> reason for parks to test trains full of water dummies. Yet, they all
>> do it.
>
>I'm not the one saying that frictional forces are unimportant -- you're the
>one who called them "relatively negligable" and insisted that the
>difference in potential energy is more important. To illustrate how
>important the frictional forces actually are in affecting the speed, I
>simply pointed out that without them, a heavy train would go just as fast
>as a light train. I never said that frictional forces don't exist.
>
>In any case, you've proved my point that frictional forces cause heavier
>trains to go faster than lighter trains. Thank you.
>
My argument was always that the inital P energy is the only difference
between the light and heavy trains. And that is correct.
Joe Schwartz
> Well, my 3 semester A's were at Purdue University. I said that not to
> start a "my university is better than yours" argument, but simply to
> show that I do have the background for this argument. Like I said,
> this is science, there is but one true answer. It's not like all the
> other arguments where there is not necessarily a correct answer, and
> all opinions matter. If you don't have the background, you shouldn't
> enter it. And to bluntly say someone is wrong, is a very ballsy thing
> to do.
Indeed, it is a very ballsy thing to do. In this case, you *were* wrong,
so I was justified in saying so.
Likewise, it is very ballsy for you to pretend that you know more about
physics than everyone else on RRC:
> I suggest you choose your fights with me, and this is one should NOT
> choose.
Perhaps next time, you'll think twice before trying to inflate your ego.
At the very least, you should practice recognizing and admitting your own
mistakes.
Joe Schwartz
> My argument was always that the inital P energy is the only difference
> between the light and heavy trains. And that is correct.
Wrong again. Initial potential energy is *not* the only difference between
the light and heavy trains. They also have different amounts of mass, and
that difference counteracts the difference between potential energy.
I'll say it again: The difference in potential energy between a light and
heavy train does not cause any difference in velocity. It's only the
frictional forces that cause a difference in velocity, because some of
those forces do not vary with the train's mass.
Give it a rest, Rastus. You made a mistake. Admit it and move on.
Wolf
> The frictional losses are greater in the cold since the grease is more
> viscous. But, filling the train and therefore giving it more energy
> from the lift hill, gives it more energy through the rest of the ride.
> All other things being basically constant.
track creates more heat, which, in turn, lowers the viscosity of the grease.
Ain't physics grand?
--
|\-/|
<0 0>
=(o)=
-Wolf
Rastus O'Ginga
wrote:
>Rastus O'Ginga <ras...@insync.net> wrote:
>
>> My argument was always that the inital P energy is the only difference
>> between the light and heavy trains. And that is correct.
>
>Wrong again. Initial potential energy is *not* the only difference between
>the light and heavy trains. They also have different amounts of mass, and
>that difference counteracts the difference between potential energy.
>
>I'll say it again: The difference in potential energy between a light and
>heavy train does not cause any difference in velocity. It's only the
>frictional forces that cause a difference in velocity, because some of
>those forces do not vary with the train's mass.
>
I'll say it again: The difference in frictional forces between the
heavy and light trains is basically negligible. Ergo, the only real
difference in the amount of energy the trains have is the initial
potential energy. Since the heavier train has more potential energy
to begin with, and it loses about the same to friction as the light
train, it has more energy at the bottom of the hill with respect to
its mass, which makes it go faster. As soon as you find a park that
tests its trains empty on the first run of a coaster, THEN I'm wrong.
You and I are saying very similar things, only from two different
angles. The difference is, you are be very pompus in your responses
(which is similar to the other two RPI grads I've dealt with in my
life, so I definitely believe that's where you went to school).
>Give it a rest, Rastus. You made a mistake. Admit it and move on.
>
I made no mistake. But, I also don't necessarily believe you made a
mistake. Difference is I'm not TRYing to make you look bad. Since
I'll be gone for the next 3 days you can crow all you want about it,
if that makes you feel better/smarter.
>------------------------------------------------------------------
>Joe Schwartz (j...@joyrides.com) -- 5 Broadway #407, Troy, NY 12180
>
> Come visit the Joyrides website <http://www.joyrides.com>,
>a photo gallery celebrating the joy and beauty of amusement rides!
Rastus O'Ginga
wrote:
>Rastus O'Ginga <ras...@insync.net> wrote:
>
>> Well, my 3 semester A's were at Purdue University. I said that not to
>> start a "my university is better than yours" argument, but simply to
>> show that I do have the background for this argument. Like I said,
>> this is science, there is but one true answer. It's not like all the
>> other arguments where there is not necessarily a correct answer, and
>> all opinions matter. If you don't have the background, you shouldn't
>> enter it. And to bluntly say someone is wrong, is a very ballsy thing
>> to do.
>
>Indeed, it is a very ballsy thing to do. In this case, you *were* wrong,
>so I was justified in saying so.
Everything I said is sound scientifically. If that is wrong in your
case, maybe RPI teaches about a different universe than Purdue does.
>
>Likewise, it is very ballsy for you to pretend that you know more about
>physics than everyone else on RRC:
Never pretended that, I simply backed my initial statements, since
they were true.
>
>> I suggest you choose your fights with me, and this is one should NOT
>> choose.
>
>Perhaps next time, you'll think twice before trying to inflate your ego.
>At the very least, you should practice recognizing and admitting your own
>mistakes
.Actually, I stated the explanation of the problem at hand. YOU were
the one saying someone was wrong when they weren't.
I've made no mistake here. People with large egos try to make other
people look stupid by saying they are wrong when they aren't (sound
familiar).
I doubt anyone else on this group is reading this thread anymore, so I
don't know what the big deal is. LIke I said, I'll be gone for 3
days, so you can be Lord of the Group if you wish.
Dave Sandborg
<ras...@insync.net> wrote:
> I'll say it again: The difference in frictional forces between the
> heavy and light trains is basically negligible. Ergo, the only real
> difference in the amount of energy the trains have is the initial
> potential energy.
OK, I see where you're coming from here.
> Since the heavier train has more potential energy
> to begin with, and it loses about the same to friction as the light
> train, it has more energy at the bottom of the hill with respect to
> its mass, which makes it go faster.
Fair enough. Now that I understand you, I think this works as an
explanation. (In this I disagree with Craig--there can be multiple correct
explanations for a phenomenon--which does not mean that all explanations
are correct, of course.) *But* note that you *have* to mention friction in
the explanation for it to work. The reason why is because without it, the
potential energy difference would make *no* difference in train speed.
This is what Joe and Craig have been saying all along, and the point which
you seem to keep missing.
> As soon as you find a park that
> tests its trains empty on the first run of a coaster, THEN I'm wrong.
Joe and Craig never disputed this, and it is not implied by their
arguments. Hence I still think you misunderstand them.
> You and I are saying very similar things, only from two different
> angles. The difference is, you are be very pompus in your responses
> (which is similar to the other two RPI grads I've dealt with in my
> life, so I definitely believe that's where you went to school).
Rastus, you yourself admitted to being pompous to Joe in another post in
this thread! Not to mention advising Craig to taking HS physics.
Please...
Craig
This has become an interesting exchange, though I can sense that the level
of frustration among all of the participants is growing. I think that all
of us agree that the answer to the question "How can we account for the
difference is speeds of coaster trains of differing weights?" is not a
matter of taste or opinion. There is an objectively correct answer, as you
have stated several times. Therefore, I thought I would make one more
attempt to explain why I think the objectively correct answer to this
question is not the answer you have provided. Here goes!
In one of your previous posts, you made this statement in summary of your
argument.
"My argument was always that the inital P energy is the only difference
between the light and heavy trains. And that is correct."
Let me explain one more time why that statement is incorrect. You are
obviously a pretty bright guy and you definitely have a technical
background, so you should have no problem following my logic.
For a few moments, lets shift our focus from coaster trains rolling on track
to the classic case of two obejcts falling in a perfect vaccum. Lets assume
that we have a feather and a bowling ball elevated 10 feet off the ground in
a perfect vaccum. Because the bowling ball has much more mass than the
feather, it has much more gravitational potential energy than the feather
(PE = m * g * h). You and I both know that if we drop these objects at the
same time, they will reach the ground at the same time, with the exact same
velocity.
Think about that. The only difference between the light and the heavy
object is their initial P energy, yet when they hit the ground they will be
going the same speed. Therefore, we can conclude that in a gravitational
field, differences in initial potential energy (assuming the initial height
is constant) does NOT affect the final speed of the objects. We started
with different potential energies, yet we ended with the same exact
velocity. The initial P did not cause the more massive object to be moving
faster than the less massive object when it hit the ground. This is why
your statement "...that the inital P energy is the only difference between
the light and heavy trains" is incorrect. Its is right to say that there is
a difference in initial P, but it is wrong to conclude that it is this
difference that causes the difference in their speeds at the bottom of the
hill. If initial P was able to cause this difference, then we would also
see this effect with the bowling ball and feather, BUT WE DONT.
This leads to the next logical question. If the difference in initial P is
not causing the difference in the speeds of the trains, what is?????????
Well, lets take another look at the feather and the bowling ball. As you
have previously pointed out, in the real world frictional forces (energy
losses) do exist. Therefore, lets take the bowling ball and the feather out
of the vaccum chamber and drop them from the same height in air. We both
know what happens. The bowling ball hits the ground quickly while the
feather slowly flutters around and lands long after the ball. Air drag
created the difference in speeds of the two objects. Therefore, when
differences in frictional forces exists, they can cause differences in
speeds of coaster cars.
But you may argue that the difference between the fricitional and drag
forces of the light and heavy coaster cars is insignificant...and you are
probably correct, but this is where you continually make your mistake! Now
think about this....
Though the difference between the air drag forces of the heavy and light
coaster cars is insignificant, the magnitude of the forces themselves may be
high. It would not suprise me if the air drag force of a PTC coaster train
traveling at 60 mph were several hundred pounds applied opposite the
direction of motion. If both the heavy and the ligh train is experiencing
this same drag force, which train do you think is going to decelerate more
as a result of this drag force??? (remember F=ma?). Because the heavier
train has more mass, its speed isn't affected as much by the drag force as
the lighter train's speed. Do you see? Air drag is not negligable, it is
significant. Yet the heavy train responds differently to the air drag than
the light train does.
The same is true for trains running in cold weather. You asked why parks
like to run trains full when it is cold. The reason is that cold weather
increases the viscosity of the grease in the bearings, thus creating larger
than normal drag forces in the bearings. A heavier train will not be slowed
down as much by these drag forces as a lighter train NOT BECAUSE IT HAS MORE
STORED ENERGY, but because it has MORE MASS!! Frictional forces cannot
decelerate a more massive train as much as they can a less massive train.
(The equation is a = F / m, not a = F / energy).
Well Rastus, that is the best I can do. I know that was long-winded, but I
could not think of any other way to exlain it. If you still disagree, all I
can do is throw my arms up in the air and walk away.
Later!
Craig
> heavy and light trains is basically negligible.
Yes, the DIFFERENCE might be negligable, but the forces themselves are not!
For instance:
Lets say the air drag force on the heavy train is 475 lb opposite the
direction of motion, but the air drag force on the light train is 470 lb
opposit the direction of motion. The difference is negligable (only 5 lb),
but the forces themselves are significant and affect the trains differently
because the trains have different masses. The heavy train doesn't slow down
much due to its 475 lb drag force, but the light train does. This is a
function of the train mass, not the train energy.
Wolf
> object is their initial P energy, yet when they hit the ground they will
be
> going the same speed. Therefore, we can conclude that in a gravitational
> field, differences in initial potential energy (assuming the initial
height
> is constant) does NOT affect the final speed of the objects. We started
> with different potential energies, yet we ended with the same exact
> velocity. The initial P did not cause the more massive object to be
moving
> faster than the less massive object when it hit the ground. This is why
> your statement "...that the inital P energy is the only difference between
> the light and heavy trains" is incorrect. Its is right to say that there
is
> a difference in initial P, but it is wrong to conclude that it is this
> difference that causes the difference in their speeds at the bottom of the
> hill. If initial P was able to cause this difference, then we would also
> see this effect with the bowling ball and feather, BUT WE DONT.
world sim. If I'm not mistaken, he was assuming both air resistance and
friction, which would tend to make him correct.
[Remember, while the bowling ball and feather hit at the same speed, the
bowling ball hits much harder...]
Greg Harbin
Rastus O'Ginga wrote:
>
> Energy is everything. The train gets energy on the hill, and loses it
> to friction throughout the ride. The friction losses are reletively
> equal, but the initial P energy is more for the heavy train.
>
> Everything else is just splitting hairs.
>
> >BGTG...@aol.com (remove "ToTRules" to reply)
> >***************************
> ><a href="http://members.tripod.com/jkdesigns/intro.htm">JK Designs</a>.
> >Take a look!
>
> Rastus O'Ginga
>
> Winner of the 2nd Annual C. Montgomery Burns Award for Outstanding Achievement in the Field of Excellence.
>
Well...
ALL objects are accelerated by gravity at the same rate. This was proven
empirically at a certain leaning tower a very long time ago. Today's
physics supports that as well. This is a fact. Start from that point.
Energy considerations will affect the impact of an object when it hits
bottom, but they won't affect the speed when it hits. There is more
momentum (mv) in a heavier object, so it takes more energy to divert it
from its course. This makes it harder to slow down. It also makes an
impact more energetic, but that doesn't affect the velocity produced by
gravity.
Heavier coasters DO have more friction. It also TAKES more friction to
slow them down. They also can slide past more wind resistance than
lighter coasters of equal aerodynamic properties. You can cut down on
the friction and wind resistance, but apart from THAT, any two objects
will accelerate at the same speed regardless of their masses.
About conferring potential energy through the chain drive, I think this
is both right and wrong. It IS true that the chain supplies energy that
works against gravity to get a train o the top of the hill, but once the
train is there, it really doesn't remember this. Once at the top of the
hill, it really doesn't matter HOW the train got there. Potential energy
is determined only by the possible drop and the mass of the object. A
fifty foot lift hill provides exactly the same potential energy as a
drop off a fifty foot cliff.
Greg Harbin
high school physics. All objects are accelerated at the same rate by
gravity. Higher massed objects have more kinetic energy at the end of a
fall because of their higher mass, not because their velocities are
greater. Very basic. Rastus, I see your point, but you might as well be
saying that the sun rises in the northeast in the US! Close, but just
not quite right.
Rastus O'Ginga wrote:
>
> On Sun, 13 Feb 2000 17:43:33 GMT, Joe Schwartz <j...@joyrides.com>
> wrote:
>
> >Rastus O'Ginga <ras...@insync.net> wrote:
> >
> >> On Sun, 13 Feb 2000 05:02:15 GMT, Joe Schwartz <j...@joyrides.com>
> >> wrote:
> >>
> >> >I never said you were wrong on that. The energy levels of the two trains
> >> >*are* different, just as you said. But their velocities are equal (or
> >> >rather, they would be equal if not for friction).
> >>
> >> Your parenthetical statement is the key. See my other post for the
> >> explanation.
> >
> >Yes, my parenthetical statement is the key. As I originally said, friction
> >is the *only* reason why a heavy train goes faster than a light train.
> >
> >> >> How many college level physics and thermodynamics courses have you
> >> >> taken? I took three and got an A and 2 B's.
> >> >
> >> >I took three and got three A's. My three-of-a-kind beats your pair.
> >>
> >> Actually depends on the University, but that's a whole other story.
> >
> >My three A's were from Rensselaer Polytechnic Institute, as were my B.S.
> >and my 4.0 GPA. Please feel free to share your credentials.
> >
>
> Well, my 3 semester A's were at Purdue University. I said that not to
> start a "my university is better than yours" argument, but simply to
> show that I do have the background for this argument. Like I said,
> this is science, there is but one true answer. It's not like all the
> other arguments where there is not necessarily a correct answer, and
> all opinions matter. If you don't have the background, you shouldn't
> enter it. And to bluntly say someone is wrong, is a very ballsy thing
> to do.
>
> Actually I've argued the RPI vs Purdue thing before (engineering that
> is). RPI is similar to many other small schools. Locally everyone
> praises it, and this gives the alumni big heads. Nationally, however,
> they are relatively unknown, similar to Rose Hulman (a very similar
> expensive private school in Indiana that you probably have never heard
> of).
>
> Pure grades come down to how hard you study for them, and what level
> of class you took.. That is to say the engineers at Purdue took much
> more difficult Physics courses than other-majored students.
>
> I usually use the Engineer in Training test as a true guide. I passed
> it, and would consider all others who passed it to have similar
> engineering abilities as I do, regardless of the school they went to.
>
> >------------------------------------------------------------------
> >Joe Schwartz (j...@joyrides.com) -- 5 Broadway #407, Troy, NY 12180
> >
> > Come visit the Joyrides website <http://www.joyrides.com>,
> >a photo gallery celebrating the joy and beauty of amusement rides!
>
Craig
> world sim. If I'm not mistaken, he was assuming both air resistance and
> friction, which would tend to make him correct.
I only ignored drag and frictional forces in order to examine just the
effects of gravity. If you read the rest of my post I then considered them.
The problem is in Rastus' application of the frictional forces. Rastus says
the difference in frictional forces on the trains is negligible, therefore
frictional forces CAN'T be causeing the difference in velocity. That is
wrong. Even if the frictional forces are exactly the same on both trains,
the lighter train slows down quicker than the heavy train as a result of
those forces because it has less mass. Remember....a force that is applied
to an object cause an acceleration (or in this case a deceleration) in
proportion to its mass.
Jeff & Sandy
Well, after almost a week of ignoring the thread, if glad to see the words *momentum* and *inertia* have left the lexicon. So far, nearly everyone has a clue as to what is going on, however, if you want THE right answer...........and yes there is only one;
start working the following into your thoughts......(1) nonconservative forces acting on the train and (2) the concept of Work. You'll find that the square of the final velocity is inversly proportional to the mass of the train amongst other things.
Have fun and I'll monitor the progress of the thread a little closer this week. Just remember, *a little bit of knowledge is a dangerous thing* :o)
Jeff
- That's just my opinion, I could be wrong -
--
ÐÏ à¡± á
Here comes Speed Racer!
<ras...@insync.net> wrote:
>
>>
>
>Well, my 3 semester A's were at Purdue University. I said that not to
>start a "my university is better than yours" argument, but simply to
>show that I do have the background for this argument.
>
>Winner of the 2nd Annual C. Montgomery Burns Award for Outstanding Achievement in the Field of Excellence.
>
too late ... this is silly
It'll Never Be Fast Enough!
Speed
Joe Schwartz
> Since the heavier train has more potential energy to begin with, and it
> loses about the same to friction as the light train, it has more energy
> at the bottom of the hill WITH RESPECT TO ITS MASS [emphasis added] which
> makes it go faster.
Finally, you have demonstrated a glimmer of understanding by adding that
crucial phrase, "with respect to its mass". Simply having more energy
would not necessarily make the heavier train go faster. But having more
energy with respect to its mass (in other words, divided by its mass)
*does* make it go faster.
Getting back to the Subject line, the *cause* of the speed difference is
the loss due to friction -- in your words, the fact that the heavier train
"loses about the same [energy] to friction as the light train." This is
what I've been saying all along, that the speed difference is caused by
frictional forces that do not vary with the train's mass.
Joe Schwartz
> I've made no mistake here. People with large egos try to make other
> people look stupid by saying they are wrong when they aren't (sound
> familiar).
People with large egos also make themselves look stupid by being unable to
recognize or admit when they are wrong. Sound familiar?
Let's face it, we both have large egos. I didn't specifically try to make
you look stupid -- I simply pointed out your mistake. Your mistake doesn't
make you look stupid. It's only your own stubbornness that makes you look
stupid.
Granted, I was extremely blunt when pointing out your mistake. For that, I
make no apology. Had it been anyone else's mistake, I would have been much
more considerate. However, it should come as no surprise that I dislike
you, so I made no attempt to spare your feelings. If you think I made you
look stupid, so be it.
Joe Schwartz
> Well, after almost a week of ignoring the thread, if glad to see the
> words *momentum* and *inertia* have left the lexicon. So far, nearly
> everyone has a clue as to what is going on, however, if you want THE
> right answer...........and yes there is only one;
>
> start working the following into your thoughts......(1)
> nonconservative forces acting on the train and (2) the concept of Work.
> You'll find that the square of the final velocity is inversly
> proportional to the mass of the train amongst other things.
Inversely proportional? I think you're the first person in this thread to
claim that the train's velocity *decreases* as its mass increases.
Jeff & Sandy
Thanks for the clarification Joe
Jeff
- That's just my opinion, I could be wrong-
--
邢 唷��
Rastus O'Ginga
wrote:
>Rastus O'Ginga <ras...@insync.net> wrote:
>
>> Since the heavier train has more potential energy to begin with, and it
>> loses about the same to friction as the light train, it has more energy
>> at the bottom of the hill WITH RESPECT TO ITS MASS [emphasis added] which
>> makes it go faster.
>
>Finally, you have demonstrated a glimmer of understanding by adding that
>crucial phrase, "with respect to its mass". Simply having more energy
>would not necessarily make the heavier train go faster. But having more
>energy with respect to its mass (in other words, divided by its mass)
>*does* make it go faster.
>
>Getting back to the Subject line, the *cause* of the speed difference is
>the loss due to friction -- in your words, the fact that the heavier train
>"loses about the same [energy] to friction as the light train." This is
>what I've been saying all along, that the speed difference is caused by
>frictional forces that do not vary with the train's mass.
>
Thanks for your approval. I could probably get a Masters degree
granted on this post alone. I was so wrong in my posts and am quite
glad that you pointed that out for me. It's nice to know we have a
Physics professor on the group who can boldly claim people as wrong in
their totally correct explanations of roller-coaster phenomena just
because they don't explain it like said professor would.
Gee, you're a swell guy.
>------------------------------------------------------------------
>Joe Schwartz (j...@joyrides.com) -- 5 Broadway #407, Troy, NY 12180
>
> Come visit the Joyrides website <http://www.joyrides.com>,
>a photo gallery celebrating the joy and beauty of amusement rides!
Rastus O'Ginga
Rastus O'Ginga
wrote:
>Rastus O'Ginga <ras...@insync.net> wrote:
>
>> I've made no mistake here. People with large egos try to make other
>> people look stupid by saying they are wrong when they aren't (sound
>> familiar).
>
>People with large egos also make themselves look stupid by being unable to
>recognize or admit when they are wrong. Sound familiar?
>
>Let's face it, we both have large egos. I didn't specifically try to make
>you look stupid -- I simply pointed out your mistake. Your mistake doesn't
>make you look stupid. It's only your own stubbornness that makes you look
>stupid.
>
>Granted, I was extremely blunt when pointing out your mistake. For that, I
>make no apology. Had it been anyone else's mistake, I would have been much
>more considerate. However, it should come as no surprise that I dislike
>you, so I made no attempt to spare your feelings. If you think I made you
>look stupid, so be it.
>
(users heart breaks)...
gias...@student.harmonytx.org
opas...@gmail.com
> Hi:
>
> My elementary-school-age child and I are doing a school science
> project. We need your help!
>
> Here is our question, which is also the title of our project:
>
> "Do heavier roller coaster cars go faster?"
>
> We built a model and in our experiment, we found that a coaster car
> with added weights goes faster.
>
> So here's our question:
>
> WHY do heavier coaster cars go faster?
>
> We know that Galileo discovered that heavy and light objects fall at
> the same speed.
>
> So why does a heavy coaster car go faster than a light coaster? Does
> the weight help to break the friction holding the coaster car in place?
>
> Please post your answer to the newsgroup and/or e-mail me at:
>
> neilkoomen (at) hotmail (dot) com
>
> Thank you in advance for your answer. If you could answer by Monday
> night (2/7/2000), we would greatly appreciate it.
>
> Thank you,
> Neil
>
>
> Sent via Deja.com http://www.deja.com/
> Before you buy.
David H.--REMOVE "STOPSPAM" to reply
wrote:
>Well the less friction applied the faster the roller coaster will go. In this case the heavier coaster has less friction than the coaster with less weight so the heavier coaster will go faster than the one with less weight.
because the more weight would be pressing harder against the track, causing
more friction.
Try to push an empty box and a heavily full box across the floor. The
lighter box has less friction because it's not rubbing as hard against the
floor.
I believe that the reason heavier coaster trains go faster is because they
have more momentum. Mass is a multiplying factor in momentum. And to be
more specific, it's not that they go faster; it's that they'll maintain
their speed longer. They'll both be going the same speed at the top of the
first hill, and likely at the bottom. But the heavier train will have more
momentum and maintain it's higher speed, despite the higher friction, which
is lessened by the wheels.
"With the first link, a chain is forged. The first speech censured,
the first thought forbidden, the first freedom denied, chains us
all irrevocably." -Capt. Jean-Luc Picard
"The Drumhead", _Star Trek: The Next Generation_
Ron
>I believe that the reason heavier coaster trains go faster is because they
>have more momentum. Mass is a multiplying factor in momentum. And to be
>more specific, it's not that they go faster; it's that they'll maintain
>their speed longer. They'll both be going the same speed at the top of the
>first hill, and likely at the bottom. But the heavier train will have more
>momentum and maintain it's higher speed, despite the higher friction, which
>is lessened by the wheels.
would rise higher on its travels. We know that not to be the case.
Any speed advantage the heavier coaster gets is due to drag. In the
same way that a lead weight falls faster than a feather, a heavy
coaster
falls faster than a lightly-loaded coaster. A heavier coaster also
better overcomes the drag of the heavy grease in the bearings.
--
Ron
surfd...@aol.com
Bill Steele
it back, and so will swing more times. The heavier coaster car will have
more stored energy at the top of the first drop, so it will accelerate
to a faster speed and should run faster for a longer time. Friction is a
wild card. Have to experiment on two coasters with identical friction.
Bill Steele
> Well the less friction applied the faster the roller coaster will go. In this case the heavier coaster has less friction than the coaster with less weight so the heavier coaster will go faster than the one with less weight.
>
The heavier car will press down harder on the wheels and axles,
resisting their rotation and slowing the coaster, just as pressing
harder on then brakes of your car slows it more than pressing the pedal
gently.The frictional force slowing the wheels is the coefficient of
friction (how rough the things sliding across each other are) times the
force pushing them together.Forget about friction between the wheels and
the trackl; that's why we have wheels instead of skids.
But a heavier coaster train acquires more energy on the first downhill
run and should coast faster after that. Minus a bit for the friction.
Hopefully the designers will have taken that into account. That's why
there will be more drops. Ideally they will seriously lubricate the wheels.