Speed Limits and Insurance ( was Re: The Latest Attack on SUV
student-mechanic
you are on the road, the more exposure you have to being hit.
The lower the speed limit, the more overtaking. Overtaking is a prime reason
for head-ons, especially at night when distance judging is problematic.
Posting lower speed limits doesn't slow the traffic. Speeders will continue
to speed and the rest of the driving public just follow the natural flow of
traffic, which is independent of speed limits.
Those who cause accidents must be made to pay for their lack of driving
skills: fines, revoking of license, jail, lawsuits. The others, we don't have
to worry about, even if they drive too fast or too slow.
Lower speed limits cannot save lives at speeds less than about 30 mph, which
is the maximum survivable crash speed. If you don't believe me, just look at
those controlled crashes the factories are forced to make. Do you think your
body is stronger than the steel cars, which get completely destroyed in those
30 mph crashes?
The speed limit should be "reasonable and safe." If this sounds vague, so
much the better. Less tickets. If an accident occurs, the one at fault
violated the rules of the road, unreasonable or unsafe speed just one possible
factor. And what is safe for an experienced, skilled driver in good machinery
is something quite different for a novice, clumsy driver in a jalopy.
.
Jeff Strickland
it has nothing whatsoever to do with the vehicle at all.
If you are going to come up with "solutions", try and keep them within the
context of the 'problem".
"student-mechanic" <s-m...@msn.com> wrote in message
news:argtj4$r27$1...@feed.centurytel.net...
Nosey
which
> is the maximum survivable crash speed. If you don't believe me, just look
at
> those controlled crashes the factories are forced to make. Do you think
your
> body is stronger than the steel cars, which get completely destroyed in
those
> 30 mph crashes?
The *impact* is tested at 30 MPH. I can be going 90 MPH when I lose control
of my vehicle, skid for a good distance, and then hit a tree at 30 MPH. If I
were only doing 60 MPH when losing control, that impact would be much slower
or not even happen at all. I probably wouldn't even lose control at 60 MPH
in the first place!
EdC
you are on the road, the more exposure you have to being hit.
Soooooo if we traveled infinitly fast. There'd be no accidents (besides
the fact that we could be everywhere all the time.
Your logic fails to take into account that human reaction time is a
constant, the more distance we need to make that reaction in time.
BTW, LOL, ROTF, WIWMTRSOP (Wishing I'd Wasted My Time Reading Some Other Post!
--
Ed in Vegas, '94 YJ
It is a truly unfortunate accident of the English language
that the words JEEP and CHEAP rhyme.
Lloyd Parker
"student-mechanic" <s-m...@msn.com> wrote:
>The lower the speed limit, the more time you are on the road. The more
time
>you are on the road, the more exposure you have to being hit.
So in stalled traffic, your chances of dying must go WAY up!
>
>The lower the speed limit, the more overtaking. Overtaking is a prime
reason
>for head-ons, especially at night when distance judging is problematic.
Speed limits didn't change on many 2-lane roads, just interstates.
>
>Posting lower speed limits doesn't slow the traffic. Speeders will
continue
>to speed and the rest of the driving public just follow the natural
flow of
>traffic, which is independent of speed limits.
And now you've got people doing 85-95; not that many when the limit was
lower.
>
>Those who cause accidents must be made to pay for their lack of driving
>skills: fines, revoking of license, jail, lawsuits. The others, we
don't have
>to worry about, even if they drive too fast or too slow.
>
>Lower speed limits cannot save lives at speeds less than about 30 mph,
which
>is the maximum survivable crash speed.
You really must move beyond the 1950s.
> If you don't believe me, just look at
>those controlled crashes the factories are forced to make. Do you
think your
>body is stronger than the steel cars, which get completely destroyed in
those
>30 mph crashes?
The cars get destroyed absorbing the energy precisely so you CAN
survive.
>
>The speed limit should be "reasonable and safe." If this sounds vague,
so
>much the better. Less tickets.
No more, as it will be up to each police officer what is reasonable and
safe. Do you want to be driving along, not knowing what each officer
considers reasonable?
>If an accident occurs, the one at fault
>violated the rules of the road, unreasonable or unsafe speed just one
possible
>factor. And what is safe for an experienced, skilled driver in good
machinery
>is something quite different for a novice, clumsy driver in a jalopy.
>
>..
>
snoopdawg47
making it equal to hitting a wall at 60 Mph. Big crash, sure! but its
perfectly survivable. And thats for head ons. Most of the accidents you see
going down the highway is just someone loosing control and slip aroudn for a
while ending up off the road (not too bad, unless theres a cliff or
something..) or sideswiping another car, in which both loose control and
just slide. The only time this gets real bad is if theres no center divider
and the car hits oncoming traffic sideways, now that SUX!
"Chris Phillipo" <Xcphi...@ns.sympatico.ca> wrote in message
news:MPG.1846b4fec...@news1.sympatico.ca...
> In article <3ddc2356$1...@nopics.sjc>, kfr...@removethis.hotmail.com
> says...
> You're not going to slow down 30MPH in the time it takes you to go head
> on with an oncoming car. And if you do hit an oncoming car, you need to
> add the speeds of both cars together. 120MPH survivable?
> --
> ____________________
> Remove "X" from email address to reply.
snoopdawg47
"Lloyd Parker" <lpa...@NOSPAM.emory.edu> wrote in message
news:arish2$9ei$2...@puck.cc.emory.edu...
> In article <argtj4$r27$1...@feed.centurytel.net>,
> "student-mechanic" <s-m...@msn.com> wrote:
> >The lower the speed limit, the more time you are on the road. The more
> time
> >you are on the road, the more exposure you have to being hit.
>
> So in stalled traffic, your chances of dying must go WAY up!
Yup, you never know when those pigeons will run into you when your parked on
the highway in a convertible.... Or what if a wild boar comes out and
attacks you! :)
> > If you don't believe me, just look at
> >those controlled crashes the factories are forced to make. Do you
> think your
> >body is stronger than the steel cars, which get completely destroyed in
> those
> >30 mph crashes?
>
> The cars get destroyed absorbing the energy precisely so you CAN
> survive.
Just to add to your point, the cars are DESIGNED to be destroyed and act
like a cushion (yes a pretty damn tough one) to protect the driver
frostalicious
> aadri...@comcast.net says...
>> If both cars are doing 60, that would neutralize all kinetic energy,
>> hence making it equal to hitting a wall at 60 Mph. Big crash, sure!
>> but its
Chris Phillipo wrote:
> What??? If both cars are doing 60 then the combined impact is 120.
> It's like hitting a wall at 120, perfectly deadly.
Slept through high school physics class, did we?
-- frosty
snoopdawg47
"Chris Phillipo" <Xcphi...@ns.sympatico.ca> wrote in message
news:MPG.1846feb0...@news1.sympatico.ca...
> > survive.
> >
> > Just to add to your point, the cars are DESIGNED to be destroyed and act
> > like a cushion (yes a pretty damn tough one) to protect the driver
> >
> >
> >
>
> Oh boy can we start another SUV vs. shitbox cars debate or just join one
> already in progress? :)
snoopdawg47
crash! wow! no wonder dragsters crash, the must WANT to go faster... no
seriously, if you have two items that crumple up (like a car) and you ram
them into each other (presuming they are close to the same weight) they
would stop dead in their tracks. The only time you would ever get even close
to getting twice the impact you would normally was if you were to have a
head on with something monstrously big (like a train going 60 mph). If an
SUV runs into a "shitbox" (as you call it) at 60 mph evenly, the shitbox
would probably feel a collision of 70mph while the SUV would be about 50
(cuz the suv is notably heavier, and hence should push the car back a bit).
"frostalicious" <johnNOSPA...@direcNOSPAMpc.com> wrote in message
news:PAaD9.18637$NV.3...@news.direcpc.com...
Mike...@mailcity.com
snoopdawg47
60 mph, that would mean you would crash at 240MPH!!!! (in case you cant tell
im being sarcastic..)
<Mike...@mailcity.com> wrote in message
news:3DDD5185...@mailcity.com...
Marc
>In article <4CudnQgXJKo...@comcast.com>, aadri...@comcast.net
>says...
>> making it equal to hitting a wall at 60 Mph. Big crash, sure! but its
>
>like hitting a wall at 120, perfectly deadly.
Not even close. If you are talking about combined energy, then the
total energy involved is about the same as an 85 mph crash into a
wall.
If you are talking about combined momentum, then a car hitting an
immobile object at 60 is the same as hitting an immobile object at 60.
It does not matter that one immobile object is a wall and the other is
immobile because it was of equal momentum.
The combined speed being double only works when hitting something
excessively heavy. A motorcycle at 60 into a semi at 60 would be
essentially the same as a wall at 120. But two equal sized vehicles
hitting head-on is the same as a wall for either.
Marc
For email, remove the first "y" of "whineryy"
Marc
>In article <argtj4$r27$1...@feed.centurytel.net>, "student-mechanic" <s-m...@msn.com> wrote:
>>The lower the speed limit, the more time you are on the road. The more time
>>you are on the road, the more exposure you have to being hit.
>
>So in stalled traffic, your chances of dying must go WAY up!
Your chances of crashing certainly do go up, compared to traveling
with the flow of traffic or faster.
snoopdawg47
my window cuz I wored it too confusingly :)
"Marc" <whin...@yifan.net> wrote in message
news:ag6rtukvnb3ura99l...@4ax.com...
Dmitry
axis. u guys apparently dont know jack about physics.
Dmitry
'93 Jeep Wrangler S
"snoopdawg47" <aadri...@comcast.net> wrote in message
news:pMKdncsLndp...@comcast.com...
Peter D. Hipson
Geeze, Snoop... If brains were butts, you'd have no where to sit. How,
in the world if both cars were going 60 would that neutralize the
kinetic energy? As to you other comment (tounge in cheek noted...) in
your example, there are two front end crashes, not four. Think about
it... You may have to stand while doing that thinking, however!
On Thu, 21 Nov 2002 16:02:16 -0700, "snoopdawg47"
<aadri...@comcast.net> wrote:
>but what if there were 4 cars going head on into a 4-way intersection doing
>60 mph, that would mean you would crash at 240MPH!!!! (in case you cant tell
>im being sarcastic..)
>
><Mike...@mailcity.com> wrote in message
>news:3DDD5185...@mailcity.com...
>> You just flunked that course. LOL
>>
>>
>>
>>
>> snoopdawg47 wrote:
>> >
>> > If both cars are doing 60, that would neutralize all kinetic energy,
>hence
>> > making it equal to hitting a wall at 60 Mph. Big crash, sure! but its
Peter D. Hipson
NEHOG (New England Hummer Owners Group)
as email sent to ma...@darkstar.mv.com will
checked monthly.
Harry K
> snoopdawg ur r an idiot, u cannot add it to 240 since its two different
> axis. u guys apparently dont know jack about physics.
>
> Dmitry
> '93 Jeep Wrangler S
>
Well I hope you don't think the crash is equavalent to 120. If you do,
you -also- don't know jack about physics.
Harry K
carson
The way I remember it kinetic energy is the energy of a moving body.
So if you are travelling at 60 you would have an KE of, say, 1000j.
The other guy, doing the same speed, say has a KE of 1500j. After the
crash the KE goes to Zero, for both vehicles. However, this energy
loss has to be made up (just like in braking, the KE loss is made up
by heat generated by the brakes). The greater the total KE loss at
impact, the greater the damage.
snoopdawg47
"Harry K" <turnk...@hotmail.com> wrote in message
news:751f8d35.02112...@posting.google.com...
snoopdawg47
bullshit...news:MPG.184883a63...@news1.sympatico.ca...
> In article <EQkD9.3827$ji1...@news1.central.cox.net>, mig...@cox.net
> says...
> > snoopdawg ur r an idiot, u cannot add it to 240 since its two different
> > axis. u guys apparently dont know jack about physics.
> >
> > Dmitry
> > '93 Jeep Wrangler S
>
Tracy & Sean
Is that the same as hitting head-on with a car doing 60-70 too then?
--
Sean & Tracy in Canada
1995 Dodge ACR Neon 4 Dr. Slightly modified ;-)
1998 Dodge Neon Sport 4 Dr. Played with already - bought Nov. 8/02
1997 Plymouth Neon 4 Dr. Kinda played with :-P - - - - Totalled in crash.
2-1972 250E Twin Bombardier Elan's - Resto'd
Soon to purchase a New 1500 4x4 or Ramcharger
http://www.aadtonline.com/Bios%20Files/s.gellvear.html
Fuck Daimler and buy back Chrysler!
.
"snoopdawg47" <aadri...@comcast.net> wrote in message
news:4CudnQgXJKo...@comcast.com...
snoopdawg47
"Tracy & Sean" <As...@Here.com> wrote in message
news:TDyD9.1631$ed3.1...@news20.bellglobal.com...
snoopdawg47
a wall the recoil is slightly less, ok so it feels like 65Mph, big deal
2. About the dragster in my previouis post, if you think I was serious about
that youre pretty stupid
"Chris Phillipo" <Xcphi...@ns.sympatico.ca> wrote in message
news:MPG.184885f97...@news1.sympatico.ca...
>
> > essentially the same as a wall at 120. But two equal sized vehicles
> > hitting head-on is the same as a wall for either.
> >
> > Marc
> > For email, remove the first "y" of "whineryy"
> >
>
> Hitting another vehicle is never the same as hitting a wall. What you
> are saying is that hitting a parked car of equal size to your own is
> exactly the same as hitting one that is coming at you at the same speed
> you are traveling, sorry, that's bullshit. If that were true hardly
> anyone would ever be killed in offset head ons.
snoopdawg47
> In article <wZednW-mINU...@comcast.com>, aadri...@comcast.net
> says...
> > uhm.... 120? so you would actually gain kinetic energy (speed) while you
> > crash! wow! no wonder dragsters crash, the must WANT to go faster... no
> > seriously, if you have two items that crumple up (like a car) and you
ram
>
> oncoming traffic?
>
> > them into each other (presuming they are close to the same weight) they
> > would stop dead in their tracks. The only time you would ever get even
close
> > to getting twice the impact you would normally was if you were to have a
> > head on with something monstrously big (like a train going 60 mph). If
an
>
>
> of the same size hitting head on at a combined speed of 120mph is the
> same as one car hitting a parked car at 60 mph. That's the US education
> system for you.
> --
> ____________________
> Remove "X" from email address to reply.
I never said that, a parked car slides away, so that would feel like i dono,
40mph. And youre combining speed which is where you go wrong, you have to
forces going against each other, form perspective (in a perfectly inneficent
crash, which of coure cars arent, they still react a few feet back) one car
does +60 while the other does -60, lets not think in terms of MPH anymore,
but in terms of velocity. If one car has a velocity of 60 and the other
has -60 (from perspective the - is coming towards you), when they meet each
force would cancel the other, effectively eliminating most of the momentum
of both cars(give a little bit for the slight bounce backwards). the only
time it would feel like a 120mph crash is if the velocity of the other car
is a 120 (60+(-120)=-60 (the big object pushes the smaller back)) the
difference between Initial velocity and final velocity is 120 (difference
between +60 and -60) If you still dont believe, i suggest you ram your car
into oncoming traffic and prove me wrong...
Harry K
Oh yeah Snoopdawg, I got it first off. Now Dmitrij, that looks like a
fish on.
I am amazed at how many people are convinced that two cars head-on at
60 result in each feeling an equivalent 120 mph crash.
Harry K
Peter D. Hipson
On Fri, 22 Nov 2002 17:31:13 -0700, "snoopdawg47"
<aadri...@comcast.net> wrote:
>
>I never said that, a parked car slides away, so that would feel like i dono,
Yes, it obvious you don't know!
>40mph. And youre combining speed which is where you go wrong, you have to
>forces going against each other, form perspective (in a perfectly inneficent
>crash, which of coure cars arent, they still react a few feet back) one car
>does +60 while the other does -60, lets not think in terms of MPH anymore,
>but in terms of velocity. If one car has a velocity of 60 and the other
>has -60
What kind of warped logic is that? To get -60, it would have to be
going *away* from you, not towards you. Yes, if it is going away from
you then you don't have a major crash, but that's not what you say!
> (from perspective the - is coming towards you), when they meet each
>force would cancel the other, effectively eliminating most of the momentum
>of both cars(give a little bit for the slight bounce backwards). the only
>time it would feel like a 120mph crash is if the velocity of the other car
>is a 120 (60+(-120)=-60 (the big object pushes the smaller back)) the
>difference between Initial velocity and final velocity is 120 (difference
>between +60 and -60) If you still dont believe, i suggest you ram your car
>into oncoming traffic and prove me wrong...
>
Geeze, Doggie, it's been proved thousands and thousands of times, with
many dead to boot. Monday, when you get back in school (that's the
fifth grade for you, right?) ask your teacher to explain it to you.
We're tired of telling you...
Plonk.
snoopdawg47
you. So far i've been the only one providing examples and thought processes,
and I've yet to see anything from you.
"Peter D. Hipson" <ma...@darkstar.mv.com> wrote in message
news:lr3vtus7dln9iukkl...@4ax.com...
snoopdawg47
then hold one hand in place and brace it against a wall or something, then
punch it with your remaining fist at about the same speed in the previous
statement. If you do it right it feels about the same, does for me anyways
(ouch, i hurted myself :( )news:7qgstu4a02a4la0i8...@4ax.com...
snoopdawg47
pulled your head out of your ass earlier you wouldve known i was joking
around with the 240mph 4-way...
"Peter D. Hipson" <ma...@darkstar.mv.com> wrote in message
news:7qgstu4a02a4la0i8...@4ax.com...
snoopdawg47
http://biz.howstuffworks.com/crash-test.htm?printable=1
I quote:
"35-mph frontal impact - At 35 mph (56 kph), the car runs straight into a
solid concrete barrier. This is equivalent to a car moving at 35 mph hitting
another car of comparable weight moving at 35 mph. "
"Peter D. Hipson" <ma...@darkstar.mv.com> wrote in message
news:lr3vtus7dln9iukkl...@4ax.com...
Marc
>
>> essentially the same as a wall at 120. But two equal sized vehicles
>> hitting head-on is the same as a wall for either.
>>
>> Marc
>> For email, remove the first "y" of "whineryy"
>>
>
So the damage of hitting a wall at 10 mph can never be approximated by
hitting another car, at any speed?
>What you
>are saying is that hitting a parked car of equal size to your own is
>exactly the same as hitting one that is coming at you at the same speed
>you are traveling, sorry, that's bullshit.
I am not saying that. You are obviously illiterate. You snip out the
deductions leading to my conclusion, then attack my conclusion for
being against your preconceptions.
You obviously "know" you are right, but can't think of any reason why,
other than to lie. You have lied more than once about what others
have said. I never said anything about hitting a parked car. That
you state I did is a lie. You did the same with another posted. When
you snip out the relevant material, then fabricate statements we made,
you are a liar.
>If that were true hardly
>anyone would ever be killed in offset head ons.
So you think you have a high probability of walking away from a 60 mph
trip into a solid wall, and a low probability of living through a 60
mph crash into another vehicle traveling at 60 mph?
Jim
> Chris Phillipo <Xcphi...@ns.sympatico.ca> wrote:
> >
> >> essentially the same as a wall at 120. But two equal sized vehicles
> >> hitting head-on is the same as a wall for either.
> >>
> >> Marc
> >> For email, remove the first "y" of "whineryy"
> >>
> >
> >Hitting another vehicle is never the same as hitting a wall.
>
> So the damage of hitting a wall at 10 mph can never be approximated by
> hitting another car, at any speed?
No. The physics of hitting another car is quite different than hitting a
wall, say made out of concrete or brick. When two cars collide, both cars
absorb the impact, even at 10 mph. With today's cars, they are designed to
absorb the energy of the impact as best as possible. Most bumpers today are
designed to protect against less than a 5 mph collision. With a car hitting
the wall, there is only one car to absorb the energy. A wall will absorb
very little or no energy until the force is great enough to move the wall.
This required energy is much greater than another car.
snoopdawg47
"Jim" <jim_...@r.a.c> wrote in message news:3DDFBF0D...@r.a.c...
Mike Shelley
physics class many years ago is for objects that do not deform upon
impact... If you have two equal masses, one with a velocity of 0 and the
other with a velocity of 60 and the moving object hits the stationary
object, they both would have a velocity of 30 in the same direction as the
original moving object... Cars aren't quite like that since they tend to
absorb the energy of the impact... It would be fairly easy way to do an
experiment that would show what would occur in these situations and it
wouldn't require the destruction of any vehicles... Take a piece of PVC pipe
that is large enough for a billiard ball and split it down the middle so
that it now makes a trough... Attach the center of this trough of PVC to
some surface(perhaps with a flush mounted wood screw) and bend the ends of
the trough upwards an equal amount by placing an two object of the same
thickness under the ends of the trough... Release billiard balls from each
end of the trough at the same time and mark how far they rebound after
hitting each other... Then, cut the trough in half and have the lower end of
the half-trough end in some sort of immovable object that will not absorb
energy from the impact... Release a billiard ball from the elevated end of
the half-trough and mark how far it rebounds after hitting the immovable
object... If these two marks are the same, then the scenario of two cars
hitting at 60 mph is the same as one car hitting a brick wall at 60 mph...
Note: Assuming a perfect rebound from the immovable object, the ball should
return to the same place as where you released it on the half-trough...
The problem I see is that vehicles are not the nice rebounding objects that
we're used to be thinking about in physics... If you assume that all the
energy in the crash is absorbed by the two vehicles (i.e. they are the same
mass and velocity and no rebound occurs), it seems pretty obvious that there
is twice the kinetic energy associated with the crash as would be if just
one vehicle crashed into a brick wall... That energy has to go somewhere and
it is logical to think that it goes into deformation of the vehicles and
heat generated...
Dave Milne
My Alfa Milano has its rubber bumpers mounted on hydraulic
pistons. It really makes a difference and I wish
the Jeep had its bumper on similar units.
While I would like a BFO bumper, I would rather replace a
badly bent stock bumper than straighten my chassis..
Dave.
"Mike Shelley" <mike-shelley@DIE-SPAMMER-SCUM@houston.rr.com> wrote in
message news:lK2E9.38623$Gc.9...@twister.austin.rr.com...
Peter D. Hipson
joke.
On Sat, 23 Nov 2002 09:18:50 -0700, "snoopdawg47"
<aadri...@comcast.net> wrote:
>Oh and I suggest you read fully what a write first this time, If you had
>pulled your head out of your ass earlier you wouldve known i was joking
>around with the 240mph 4-way...
>
Peter D. Hipson
Harry K
> Try this, take both your fists and ram them into each other at full speed,
> then hold one hand in place and brace it against a wall or something, then
> punch it with your remaining fist at about the same speed in the previous
> statement. If you do it right it feels about the same, does for me anyways
> (ouch, i hurted myself :( )
> "Peter D. Hipson" <ma...@darkstar.mv.com> wrote in message
> news:7qgstu4a02a4la0i8...@4ax.com...
> > (replying to massivly cross-posted crap...)
> >
> > Geeze, Snoop... If brains were butts, you'd have no where to sit. How,
> > in the world if both cars were going 60 would that neutralize the
> > kinetic energy? As to you other comment (tounge in cheek noted...) in
> > your example, there are two front end crashes, not four. Think about
> > it... You may have to stand while doing that thinking, however!
> >
> >
<snip for BW>
Peter in case you missed it. Two cars head on at 60 result in both
cars experiencing a 60mph crash not a 120mph. That is what Snoop is
saying by inference. Only someone who thinks it is 120 could have
missed that.
Harry K
snoopdawg47
being sarcastic."...news:hdp1uu4snf5hujogm...@4ax.com...
snoopdawg47
"Mike Shelley" <mike-shelley@DIE-SPAMMER-SCUM@houston.rr.com> wrote in
message news:lK2E9.38623$Gc.9...@twister.austin.rr.com...
snoopdawg47
who's right? (me), yeeeeeeees, everything is a joke....
"Peter D. Hipson" <ma...@darkstar.mv.com> wrote in message
news:hdp1uu4snf5hujogm...@4ax.com...
Marc
I don't get it. If you were to hit a wall at 10 mph, compared to
another car at 100 mph, you think that you will come away better at
the 100 mph crash because the car will absorb the energy better?
Jim Warman
There is NO neutralization of energy.... A car hitting an immovable wall at
35, is the same as a car hitting an identical car travelling at the
identical spped... where-in lies the fault to your logic. The other car has
a 60/40 chance of being bigger than yours. The other car has a 60/40 chance
of travelling faster than yours. As for the survivability of a 60mph head-on
crash.... well, that's gotta be somewhere between winning the lotto and a
miracle.
A car equal to yours, travelling the same speed as yours is, in effect, an
immovable object (much like the brick wall). At any rate, when it comes to a
collision of this nature, there are no winners.
--
Jim Warman
mech...@telusplanet.net
"snoopdawg47" <aadri...@comcast.net> wrote in message
news:zImcnVd1aKi...@comcast.com...
Ted Mittelstaedt
>>With a car hitting
>>the wall, there is only one car to absorb the energy. A wall will absorb
>>very little or no energy until the force is great enough to move the wall.
>>This required energy is much greater than another car.
>
>I don't get it. If you were to hit a wall at 10 mph, compared to
>another car at 100 mph, you think that you will come away better at
>the 100 mph crash because the car will absorb the energy better?
>
If you were to hit a wall at 10Mph you would be worse off than hitting a
pile of hay at 20Mph.
--
Ted Mittelstaedt te...@toybox.placo.com
Lloyd Parker
>Marc wrote:
>
>> Chris Phillipo <Xcphi...@ns.sympatico.ca> wrote:
>> >
>> >> essentially the same as a wall at 120. But two equal sized
vehicles
>> >> hitting head-on is the same as a wall for either.
>> >>
>> >> Marc
>> >> For email, remove the first "y" of "whineryy"
>> >>
>> >
>> >Hitting another vehicle is never the same as hitting a wall.
>>
>> So the damage of hitting a wall at 10 mph can never be approximated
by
>> hitting another car, at any speed?
>
>No. The physics of hitting another car is quite different than
hitting a
>wall, say made out of concrete or brick. When two cars collide, both
cars
>absorb the impact, even at 10 mph. With today's cars, they are
designed to
>absorb the energy of the impact as best as possible. Most bumpers
today are
>designed to protect against less than a 5 mph collision.
Used to be; this was lowered to 2.5 mph during the Reagan
administration. And all the bumpers have to do is protect safety
equipment, not sheet metal and not the bumpers themselves.
Michael Painter
"Jim Warman" <mech...@telusplanet.net> wrote in message
news:YMgE9.9008$hu.8...@news2.telusplanet.net...
> OK, you crossposting little wienie.... I see what you're getting at....
> There is NO neutralization of energy.... A car hitting an immovable wall
at
> 35, is the same as a car hitting an identical car travelling at the
> identical spped... where-in lies the fault to your logic. The other car
has
> a 60/40 chance of being bigger than yours. The other car has a 60/40
chance
> of travelling faster than yours. As for the survivability of a 60mph
head-on
> crash.... well, that's gotta be somewhere between winning the lotto and a
> miracle.
A car hitting a stationary car at 35 is not quite the same as a car hitting
a wall at 35. There is some additional energy that will be absorbed as the
hit car gets banged up a bit.
Ahead on between two cars traveling at the same speeds is similar to the
single car hitting the parked one at 70mph.
The inertia of the "other"vehicle must be taken into account.
J-rod
/me wishes he'd been around for this discussion earlier today.
why do ppl just assume you're wrong and not bother to figure out why?
(read: examples weren't given so poster could brush up his keyboarding
skillz) ;)
snoop, you have more patience than i do.
"snoopdawg47" <aadri...@comcast.net> wrote in message news:<zcicnad3TIx...@comcast.com>...
C. E. White
Imagine a very thin yet strong panel suspended in the middle of a road. It is
free to move, but is so strong it will not deform. Identical cars approach the
panel from opposite directions moving at exactly the same speed, on the same
line. They collide with opposite sides of the panel at exactly the same time.
1) Will the panel "feel" the impact? I say yes. The force will be transmitted to
the wall from both sides. However, for the purposes of my experiment we will
assume the panel is strong enough that it is not measurably deformed.
2) Will the panel move? I say no. Equal and opposite forces were applied from
both sides. They cancel out and the panel does not move.
3) What forces do each of the cars "feel"? I say they feel the same force as if
they had collided with a rigidly fastened immovable barrier (i.e., a concrete
wall). The forces applied to either car is the same.
4) What happens if the panel magically vanishes milliseconds before the cars hit
it? They run into each other. If the cars are truly identical, and truly moving
at the same speed, and truly moving on the same line from opposite directions,
then the each will see almost exactly the same collision as if they had run into
the thin panel - which is the same as if they had run into a concrete wall.
Based on this I came to the conclusion that two cars involved in a head-on
collision, where each car is traveling 60 mph is the same for each of the cars
involved as if they had individually crashed head-on into a permanent barrier at
60 mph. This is not perfectly true, but a close approximation. As soon as the
cars don't hit perfectly, then things begin to deviate from this ideal
approximation. Even a slight misalignment will result in the cars rotating as
they collide. This burns off some of the momentum that otherwise would go into
decelerating (and crushing) the cars. When you hit a fixed barrier, this doesn't
happen , so for non perfect head on collisions, a crash into a barrier is worse.
Hitting a movable object (another car) is not the same as hitting a permanent
barrier. The other car can move. I believe that hitting a similar sized parked
car at 60 mph would be like crashing head-on into a barrier at 30 mph. As the
moving car hits the other car (again assuming a "perfect" head-on collision),
the other car will be deformed in exactly the same way as the moving car and
will be accelerated backwards. The friction of the tires will add some to the
force of the collision, but the collision will certainly be far less severe than
a 60 mph crash into a fixed barrier.
Regards,
Ed White
bi...@pipping.com
One of these days, people will figure this out...
Hitting a brick wall at 70 is NOT the same as hitting a stationary
same-size vehicle at 70.
The vehicle will absorb some energy by moving; the wall will not.
Hitting a same-size vehicle head on at equal speeds is like hitting a
brick wall at the combined speed.
--
Bill
Replace "g" with "a"
Experience is what you get when you expected something else.
JaWise
>is twice the kinetic energy associated with the crash as would be if just
>one vehicle crashed into a brick wall...
Say the Kinetic enery at 35mph is 3000.
Two cars head on at 35:
Car 1 starts with 3000. Ends with 0.
Car 2 starts with 3000. Ends with 0.
One car at 35 into brick wall.
Car starts with 3000. Ends with 0.
Wall starts with 0. Ends with zero.
In each case each car is "dissipating" 3000 of kinetic energy into heat and
bending metal.
Mike Shelley
morning and I had been up all night and on top of this, my caffeine had
reached critically low levels...
About an an hour or so after I had posted the message, I realized a slight
problem with my statement that the extra kinetic energy had to go
somewhere... With two vehicles, you have twice the mass to be heated during
the conversion of the kinetic energy into heat and crumpled metal, so that
part of my argument was faulty...
As a side note, I saw a police chase on TV tonight where a car was driving
on the wrong side of the freeway and goes head-on into another car...
Supposedly both cars were doing around 70 mph at the time of the crash...
Everyone survived with a most a couple of cuts and bruises... To say the
least, the cars did not bounce back, so all their kinetic energy was
disipated in heat and bended metal... They ended up within a single car
length of each other and it's quite possible that this was due to it not
being a perfectly square hit and the vehicles rotating during the crash...
Quite a bit of bended metal though...
Assuming objects that do not heat up or deform / absorb energy during the
collision, the moving object will rebound at exactly the same speed as it
collided with the stationary object... The question that everyone seems to
be having trouble with in this discussion is what happens when two of the
moving objects hit each other... I believe that I have convinced myself that
it would be the equivalent of just one of the objects hitting an immovable
object... The way I came to this conclusion is from a device with which I'm
sure most of us are familiar... Back in the 1970s and 1980s, it was popular
to have theise desk decorations / toys that consisted of a rack from which
multiple solid steel balls were suspended by pairs of lightweight line
(nylon fishing line usually)... I happen to still have one of these items
and I pulled the two end balls apart and released them at the same time...
Upon collision, they rebounded to nearly the same place as they had started
from (they're not perfectly rebounding objects, so there will be some loss
of kinetic energy to heat and sound)... If the impact had been double as
some people are proposing for vehicles, then they would have rebounded twice
as high...
"snoopdawg47" <aadri...@comcast.net> wrote in message
news:zcicnad3TIx...@comcast.com...
Yes! finally someone who gets it :).
Mike Shelley
>>I don't get it. If you were to hit a wall at 10 mph, compared to another
car at 100 mph, you think that you will come away better at the 100 mph
crash because the car will absorb the energy better?<<
It is all about dissipating the energy over the most distance... When you
hit an immovable wall, the energy dissipation is mainly handled by the
destruction of your vehicle... I've had to lay a motorcycle down at 60 mph
and walked away from it without even a scratch... The energy was dissipated
as I slid along the pavement, but I didn't have one single body part in
contact the entire time, so I sustained no damage to my person... Some of
the guard rails on bridges these days are made of metal that has a mechanism
that allows them to curl up when a car hits them head-on... The idea here is
to dissipate the energy of the vehicle over a certain distance such that it
will allow the occupants of the vehicle to possibly survive...
Valued User
> To say the
> least, the cars did not bounce back, so all their kinetic energy was
> disipated in heat and bended metal...
..and sound
> The question that everyone seems to
> be having trouble with in this discussion is what happens when two of the
> moving objects hit each other... I believe that I have convinced myself
that
> it would be the equivalent of just one of the objects hitting an immovable
> object...
This is called an inelastic collsion.
-Me
Valued User
> >>I don't get it. If you were to hit a wall at 10 mph, compared to
another
> car at 100 mph, you think that you will come away better at the 100 mph
> crash because the car will absorb the energy better?<<
Regardless, your body would have to decelerate to 0 mph (or whatever your
unit of measurement is).
Over 1 foot, would you rather decellerate from 100-0 or 10-0.
If you can't make up your mind, drive fast and slam on the brakes until you
come to a stop. Then go back and drive slow and apply the brakes at the same
point and come to a stop at the same point as you did before.
Pretend the distance that you decellerated was narrowed down from 100 or 200
feet to 1 foot.
-Me
nullo
boast of "virgin steel".
> Just to add to your point, the cars are DESIGNED to be destroyed and act
> like a cushion (yes a pretty damn tough one) to protect the driver