Watch Your Speed
virtua...@gmail.com
times the distance traveled. So when auto companys tell us we get a
certain MPG they are lying because the ammount of force used over a
distance depends on the speed you are going. So if you travel even 5
mph under the speed limit you will save 1/5 the gasoline you use going
at 25mph. And it is even better if you coast down hills, or pump the
petal. But it is harder on your engine to shift gears when you are
changing speeds. So if America wants to do something about peak oil,
and the crisis in Iran & Iraq (Who have been embargoing us and denying
us oil without America telling the public), then we should reduce the
speed limits.
Right everybody?
ji...@specsol.spam.sux.com
> In Physics the work it takes to move an object equals the force used
> times the distance traveled. So when auto companys tell us we get a
> certain MPG they are lying because the ammount of force used over a
> distance depends on the speed you are going. So if you travel even 5
> mph under the speed limit you will save 1/5 the gasoline you use going
> at 25mph. And it is even better if you coast down hills, or pump the
> petal. But it is harder on your engine to shift gears when you are
> changing speeds.
Bunch of babble.
> So if America wants to do something about peak oil,
> and the crisis in Iran & Iraq (Who have been embargoing us and denying
> us oil without America telling the public), then we should reduce the
> speed limits.
> Right everybody?
Wrong.
Peak mileage depends on the overall design of the car.
Of the cars I've owned, the lowest speed best mileage was about 60 MPH
and the highest was about 80 MPH.
The car I currently own seems to like a tad under 70 MPH.
--
Jim Pennino
Remove .spam.sux to reply.
virtua...@gmail.com
Jim you are eating to many fried donuts because you think time is
distance. You can't engage in a formal debate either so you result to
insults. Well Jim, time isn't distance. It takes more force to make a
care drive faster, and the equation clearly proves that the distance a
car travels is the same regardless of how fast it is traveling. So
Jim, how much work does it take then?
Eh'?
> Remove .spam.sux to reply.
ji...@specsol.spam.sux.com
> Eh'?
By your convoluted logic, a car would get it's maximum mileage standing
still.
Engine efficiency is a curve function of engine rpm and has a peak value.
Vehicle speed is a direct function of engine rpm.
Drag is a direct function of vehicle speed.
Maximum effiency, or best fuel mileage, in a modern, aerodynamically
designed vehicle, usually occurs just slightly below the most
efficient rpm.
Once at cruise speed, the only force required is whatever it takes to
equal the drag.
Your post is pure babble with no understanding of how anything works.
Corey...@gmail.com
Work = Force X Distance. So obviously it takes more force to drive
faster in a car, and the same distance is traveled regardless of how
fast you are going. So if we reduce the speed limits we will save money
and gas!!!!
> Remove .spam.sux to reply.
AmerGovtCriminalsExposer
<Corey...@gmail.com> wrote in message
news:1153195794.8...@h48g2000cwc.googlegroups.com...
If you NSA and FBI PSYCHOPATHS did your job the way you are supposed to do,
gas prices wouldnt be at $3.40 - $3.50 per gallon and Exon Mobil wouldnt
have LOOTED an OBSCENE $30 bil from consumers last year.
But YOU LOW IQ PYSCHOPATHS dont care because your JOB is to MAKE SURE the
RICH CAN LOOT the POOR in America.
ji...@specsol.spam.sux.com
> Work = Force X Distance. So obviously it takes more force to drive
> faster in a car, and the same distance is traveled regardless of how
> fast you are going. So if we reduce the speed limits we will save money
> and gas!!!!
Yet another slack jawed babbler quoting an equation with no understanding
of how to apply the equation or what it means.
Corey
Then refute it, you donut eating bitch.
ji...@specsol.spam.sux.com
> If you NSA and FBI PSYCHOPATHS did your job the way you are supposed to do,
> gas prices wouldnt be at $3.40 - $3.50 per gallon and Exon Mobil wouldnt
> have LOOTED an OBSCENE $30 bil from consumers last year.
> But YOU LOW IQ PYSCHOPATHS dont care because your JOB is to MAKE SURE the
> RICH CAN LOOT the POOR in America.
Yet another babbling moron with no understanding of economics.
Company Profit margin
Microsoft 32%
Coca-Cola 22%
ExxonMobil 11%
ConocoPhillips 8%
Chevron 8%
Prevent the looting of the poor, boycott Microsoft and Coke.
ji...@specsol.spam.sux.com
Refute what, you babbling twit, your lack of basic understanding?
The force required to maintain a given speed is equal to the drag
at that speed. Drag is directly related to speed.
The efficiency of an internal combustion engine is a curve with a peak
at some rpm. Speed and rpm are directly related by the transmission
gear ratio, the axle gear ratio, and the size of the tires.
QED.
If you can't understand it, it is not my problem.
Your babbling crap is meaningless.
AmerGovtCriminalsExposer
<ji...@specsol.spam.sux.com> wrote in message
news:nb5uo3-...@mail.specsol.com...
Moron,
Software companies always have much better profit margins than other
industires.
People buy Windows XP once and use it for 3 or 4 years but people have to
BUY GAS FUCKING EVERY COUPLE OF DAYS.
Like wise people have CHOICE in buying other low priced cola products while
they are left with NO CHOICE of CHEAPER OIL.
There are plenty of other reasons I can give how gas prices affect people
more than coke or software but I dont have time for it now.
Get it blabbering idiot ?
CWatters
<virtua...@gmail.com> wrote in message
news:1153187264.7...@35g2000cwc.googlegroups.com...
> In Physics the work it takes to move an object equals the force used
> times the distance traveled. So when auto companys tell us we get a
> certain MPG they are lying because the ammount of force used over a
> distance depends on the speed you are going.
Thats why they _don't_ just quote a single MPG figure. In the UK (at least)
they quote an MPG figure for the "Urban cycle"and similar profiles. These
are industry standard driving profiles. You can argue about their validity
if you like but your OP doesn't tell the whole story.
Roy. Just Roy.
No auto company boasts a "certain" MPG. The MPG rating is an average
over many tests at different driving speeds. "City" is an average of
all speeds measured under 45 mph, and "highway" is an average of all
speeds measured over 45 mph.
It is assumed that, as you use your car, eventually all the speeds you
choose will average out to the MPG rating, given proper maintenance.
> So if America wants to do something about peak oil,
> and the crisis in Iran & Iraq [...] then we should reduce the
> speed limits. Right everybody?
That's one solution. Another solution is to reduce the weight that is
rolled. A motorcycle will get 10X the MPG as an SUV, from sheer weight
difference alone.
/Roy
Corey...@gmail.com
At one point in time people did loby to reduce the speed limits on the
highways to 55 to try and save gas, but they never passed the bill.
However look at my figuring:
An average car weighs 1500 kg
1 meters = 0.000621371192 miles
55mph = 24.5872 meters / second ^2
So the force at 55mph is 36880 newtons
But at 20 mph we see it differently: 8.94 meters / second ^2
And the force is 13410 newtons
So The work is less than half going at 20mph!!!!
And I like what the troll said, because you get free energy if you
don't move anything, and if you go up a hill really slow it doesn't
take much work, and then you can just fly down it at high speeds and
get a lot of extra free energy from gravity. Cool!!!
ianpa...@gmail.com
There are indeed very many factors. If going uphill the amount of
energy required is fixed at gMh N/m so it pays to go uphill at optimal
rpm. Going downhill you use no energy if you freewheel. On gradients
you can sometimes freewhell at over 100km/h.
Aerodynamic drag varies to the squarte of the speed but, as you say,
with an aerodynamic design this only comes in at high speed. The fact
that a car needs wheels and is on the road limits possible aerodynamic
efficiency.
In built up areas the main loss is braking and accelerating. What is
required is a regenerative braking system.
Please in a scientific user group could we use SI 130km/h NOT 80mph?
Strictly speaking SI is m/s but km/h is often used.
Mike
You are minimizing distance. Your optimum value is when d = 0, i.e.
when you are not moving.
Cars consume more gas at lower speeds and iin traffic jams.
You missed that: Work done = Change in kinetic energy
so the less the speed the more work must be done to bring the car up to
speed. If you do not do more work but keep it at the same level, the
more it will take to reach your destination and will end up even
consuming more gas. It turns out then that the conbsumption curve is
quadratic as a function of speed and it has a minimum some place around
50 MPG to 80 MPG for the majority of commercial passenger vehicles.
Mike
Igor
It's not that simple, actually. There are plenty of factors that go
into this and you would need to include them all. Speed limits have
usually been set around maximum average fuel efficiencies. When we
were still using leaded fuels with very high octanes, I recall that the
maximum average fuel efficiency occured around 55 mph, so that was the
set speed limits in the US at the time. Now that everyone is using
unleaded, we do allow for much higher speeds. I'm not sure whether
unleaded, lower octane fuels get better mileage at those higher speeds,
but some people have alluded to this. And remember that quoted MPGs
are only averages and are not meant to be taken literally, but as
ballpark figures.
As far as Iraq and Iran contributing to our energy problems right now,
that's not even close. The big factor right now seems to be
unanticipated increases in demand from Asian countries But if things
continue getting out of control in the middle east, we could be in for
some further problems.
Igor
I've always loved the way people learn a little basic physics and then
try to apply their limited knowledge to the vast real world. And this
isn't actually criticism, since I've been there myself and know whereof
I speak. The truth is that the real world is far too complex to reduce
to a simple equation. In fact, it often runs on a system of equations,
all interacting, usually nonlinear and tremendously complicated.
That's why, in cases like this, there is really no substitute for
empirical analysis.
Paul Cardinale
virtua...@gmail.com wrote:
> In Physics the work it takes to move an object equals the force used
> times the distance traveled. So when auto companys tell us we get a
> certain MPG they are lying because the ammount of force used over a
> distance depends on the speed you are going.
So, you don't understand what the mileage rating of a car means.
> So if you travel even 5
> mph under the speed limit you will save 1/5 the gasoline you use going
> at 25mph.
And you don't know how to apply physics.
> And it is even better if you coast down hills, or pump the
> petal. But it is harder on your engine to shift gears when you are
> changing speeds. So if America wants to do something about peak oil,
> and the crisis in Iran & Iraq (Who have been embargoing us and denying
> us oil without America telling the public), then we should reduce the
> speed limits.
>
> Right everybody?
Wrong. Every car has a non-zero speed at which it gets the best
mileage.
Reducing speed limits would only be an improvement if most of the cars
that
are traveling at the limit are going faster than the speed at which
they get the best mileage. Furthermore, a very large amount of auto
usage occurs well below the speed limit.
On top of that, automobiles consume only about 7% of the oil we use.
Small improvements in auto efficiency would have almost no impact on
total oil comsumption.
Paul Cardinale
tadchem
Corey...@gmail.com wrote:
<snip>
> At one point in time people did loby to reduce the speed limits on the
> highways to 55 to try and save gas, but they never passed the bill.
That became law in 1982, and was repealed in 1995.
(see http://www.ibiblio.org/rdu/nma-prsl.html for example)
Learn a little history.
> However look at my figuring:
>
> An average car weighs 1500 kg
...give or take 1000 kg. You certainly can't be thinking of comparing
a Mini to a Suburban.
> 1 meters = 0.000621371192 miles
Significant figure abuse!!! Do you *really* measure miles to the
nearest couple of nanometers?
> 55mph = 24.5872 meters / second ^2
Velocity = Acceleration???
> So the force at 55mph is 36880 newtons
You can't get there. What is your drag coefficient? Your engine power,
torque, efficiency, rolling friction, road condition, grade
(inclination), etc.?
[flush]
You'd need a BS degree to drive this idea home, and you've hardly got a
Community College Learner's Permit.
Tom Davidson
Richmond, VA
Ian Parker
>
> It's not that simple, actually. There are plenty of factors that go
> into this and you would need to include them all. Speed limits have
> usually been set around maximum average fuel efficiencies. When we
> were still using leaded fuels with very high octanes, I recall that the
> maximum average fuel efficiency occured around 55 mph, so that was the
> set speed limits in the US at the time. Now that everyone is using
> unleaded, we do allow for much higher speeds. I'm not sure whether
> unleaded, lower octane fuels get better mileage at those higher speeds,
> but some people have alluded to this. And remember that quoted MPGs
> are only averages and are not meant to be taken literally, but as
> ballpark figures.
>
No unleaded in not in itself more efficient. Improved aerodynamics is
of course a factor. Speed limits, particularly the lower limits in
built up areas are set for safety.not efficiency. Safety, as motorists
keep poining out is not unambiguously about reducing speeds and keeping
to speed limits. Indeed in Europe cruise control which keeps you to a
fixed speed is very much frowned upon. It is a truism that you should
look at the road and not the clock In general of course 50km/h is
reasonable for a built up area , but there are exceptions to this.
> As far as Iraq and Iran contributing to our energy problems right now,
> that's not even close. The big factor right now seems to be
> unanticipated increases in demand from Asian countries But if things
> continue getting out of control in the middle east, we could be in for
> some further problems.
As far as overall energy policy is concerned, the answer is clear.
Nuclear power in the short and medium term, solar power in the long
term. In the long term Asia is going to be demanding the same standard
of living as we have. New technologies will be needed for this.
A word about the supersafe society. Supersafe societies are often not
safe. Lebanon is supersafe, it has been well protected from nuclear
accidents and radiation. More people have however been killed there
than at Chernobyl. In fact the risk of developing cancer is not linear,
therre is a threshold dose. I mention Lebanon. Oil, and the dependence
of the developed world on it is very much a reason for the instability
in the Middle East. Iran is using the high oil price to buy more and
more Katushas + longer range missiles
PD
Corey...@gmail.com wrote:
>
> Work = Force X Distance. So obviously it takes more force to drive
> faster in a car,
It is not obvious at all. Cars have gears and the torque that they can
deliver actually increases with RPM, meaning that more power can be
delivered to the wheels per drop of gasoline if the engine is running
at a *higher* speed. Oversimplification of a physical situation,
frequently appended with the word "obviously", is the devil's work.
PD
Robert Weldon
"Igor" <thoo...@excite.com> wrote in message
news:1153244001.1...@35g2000cwc.googlegroups.com...
>
> virtua...@gmail.com wrote:
>> In Physics the work it takes to move an object equals the force used
>> times the distance traveled. So when auto companys tell us we get a
>> certain MPG they are lying because the ammount of force used over a
>> distance depends on the speed you are going. So if you travel even 5
>> mph under the speed limit you will save 1/5 the gasoline you use going
>> at 25mph. And it is even better if you coast down hills, or pump the
>> petal. But it is harder on your engine to shift gears when you are
>> changing speeds. So if America wants to do something about peak oil,
>> and the crisis in Iran & Iraq (Who have been embargoing us and denying
>> us oil without America telling the public), then we should reduce the
>> speed limits.
>>
>> Right everybody?
>
> It's not that simple, actually. There are plenty of factors that go
> into this and you would need to include them all. Speed limits have
> usually been set around maximum average fuel efficiencies. When we
> were still using leaded fuels with very high octanes, I recall that the
> maximum average fuel efficiency occured around 55 mph, so that was the
> set speed limits in the US at the time. Now that everyone is using
> unleaded, we do allow for much higher speeds. I'm not sure whether
> unleaded, lower octane fuels get better mileage at those higher speeds,
> but some people have alluded to this. And remember that quoted MPGs
> are only averages and are not meant to be taken literally, but as
> ballpark figures.
No, speed limits are not determined to maximize fuel efficiency, they are
based on the design speed of the roadway and other safety parameters, with a
lot of politics thrown into the mix. The US interstate highway speed limit
of 60 mph was based on the fact that that was the speed that a hatbox would
begin to slide across a rear parcel shelf in a standard radius turn. When
that speed limit was set, a significant proportion of cars on the road could
not even do the speed limit. As an interesting side note, most of the
interstate system was designed for 80 mph. The 55 mph limit was political,
and was a misguided attempt to try and lessen fuel consumption, vehicle
mileage rates versus speed were not a factor.
Randy Poe
My recollection is that at the time, the universal justification given
was that 55 mph was known to be the most efficient speed for
a car, and that there were plenty of graphs being bandied about
showing efficiency dropping off rapidly above 55 mph.
Whether it's true or not, that was the claim.
Since then, there have been a number of studies showing that
55 mph reduces the highway death rate significantly compared
to 65 mph. Of course, there have been equally as many studies
showing that 55 mph has no effect, or increases the death rate
compared to 65 mph.
- Randy
Corey...@gmail.com
States Boost Speed Limits On Major Highways
Moves Come Despite Concerns Over Safety, High Gas Prices; 80 Miles Per
Hour in Texas
By STEPHANIE CHEN, The Wall Street Journal
With gasoline prices approaching an average of $3 a gallon and Middle
East strife escalating, it might seem like a bad time to encourage
drivers to burn even more fuel. But speed limits on stretches of
freeways around the country are rising -- just in time for summer road
trips.
States around the country, including Texas and Michigan, have recently
increased speed limits on hundreds of miles of interstate highways and
freeways. Other states are expected to follow soon.
Near Detroit, drivers long confronted by signs telling them to go no
more than 55 miles per hour or 65 mph are seeing new signs with 70 mph
speed limits. By November, cruising at 70 mph will be allowed on nearly
200 miles of road, including parts of Interstate 75 and M-59, a major
suburban route. Texas has begun erecting 80 mph signs along 521 miles
of I-10 and I-20 in 10 rural western counties, giving them the highest
speed limit in the U.S. In September, Virginia is likely to boost the
speed limit on I-85 near the North Carolina border to 70 mph from 65
mph. Driving faster may get people to their destinations more quickly,
but it can also add to the rising cost of owning a car. The Department
of Energy estimates that every five miles per hour a person drives
above 60 mph costs an extra 20 cents a gallon, for a fuel-efficiency
loss of 7% to 23%, depending on the type of car and gas. That's because
higher speeds increase aerodynamic drag on a car, requiring more
horsepower. Over a year, it costs roughly an additional $180 in gas to
drive 75 mph instead of 60 mph, according to the Environmental and
Energy Study Institute, which promotes energy efficiency and renewable
energy.
Bruce Jones, director of the Minnesota Center for Automotive Research
at Minnesota State University in Mankato, calculates from federal data
that driving 75 mph, rather than 65, would increase gas expenses by
about $121 a year for a 2006 Pontiac G6 sedan and $217 for a Hummer.
But lawmakers in Texas, Michigan and other states say that raising
speed limits will make roads safer by restoring credibility to
speed-limit signs and making driving speeds more uniform. While
transportation engineers acknowledge that raising speed limits hurts
fuel efficiency, they contend that careful studies of traffic flow and
driver behavior show that many speed limits are actually too low. Most
drivers who exceed these low speed limits are doing it safely. "In
Texas, they are already going [80 mph] anyway," says Carlos Lopez,
director of traffic operations at the Texas Department of
Transportation. "People are driving where they feel comfortable."
John Stinson, a home remodeler who lives in Mount Clemens, Mich., says
the new 70 mph speed limit on the Van Dyke Expressway gives him an
extra "cushion" during his commutes of as much as 200 miles throughout
southeastern Michigan. "There won't be the slow people holding everyone
up and the fast people weaving in and out," he says.
It has long been thought that higher speed limits lead to more road
fatalities. But the link has been disputed. Many modern roads are built
to accommodate vehicles moving at faster speeds, and many drivers are
now protected by front and side airbags.
In 2005, the number of injuries per mile on the U.S. interstate-highway
system fell to the lowest level since it was established by President
Eisenhower in 1956, according to the National Highway Traffic Safety
Administration. But Russ Retting, a senior transportation engineer at
the Insurance Institute for Highway Safety, a research group funded by
auto insurers, says fatality rates were 17% higher in states that
raised speed limits from 1995 to 1999 than in states that didn't.
"It's difficult to generalize information out of all the noise," says
Karl Zimmerman, an assistant research engineer at Texas Transportation
Institute, part of Texas A&M University, adding that many crashes are
caused by weather, driver inattentiveness and road conditions that
aren't connected to speed limits.
Recent speed-limit increases in Indiana, Iowa, Michigan and Texas are
the latest in a string of jumps dating back to the 1995 repeal of the
nationwide 55 mph speed limit, mandated by Congress in 1974. More than
a dozen states quickly gave drivers the freedom to push the pedal
closer to the metal, especially in Western and Midwestern states with
less congestion, scattered populations and wide, straight interstates.
A total of 31 states now have a maximum speed limit of at least 70 mph,
according to the Insurance Institute for Highway Safety.
Shaunee Lynch, spokeswoman for the Kentucky Transportation Cabinet,
says the state agency hopes that lawmakers will agree early next year
to raise the speed limit to 70 mph from the current 65 mph to keep up
with surrounding states that already let drivers go that fast. Drivers
aren't happy when signs at the border warn them to slow down, she says.
In Louisiana, state Sen. Joe McPherson says he plans to revive his
unsuccessful bill that would have raised the speed limit on Louisiana
interstates to 75 mph from 70 mph and on limited-access freeways to 70
mph from 65 mph. "If 35 mph is more fuel-efficient than 55 mph, then
why don't we all just drive 35 mph?" he says in response to
fuel-efficiency critics.
State lawmakers typically set statewide speed limits, with
transportation officials determining which stretches of roads can
safely handle faster-moving traffic. It isn't clear if the urge to
increase speed limits on interstates will trickle down to smaller roads
and streets, usually controlled by local officials.
Speed limits for cars and trucks can vary, with Illinois restricting
truck drivers to no more than 55 mph -- or 10 mph slower than the
maximum interstate-highway speed for cars. A bid to increase the speed
limit for trucks to 65 mph was vetoed by the Illinois governor in 2004.
In Michigan, the speed limit for trucks will be raised to 65 mph by
November -- but that still keeps them slower than cars.
It is too soon to tell whether some speed demons will see rising speed
limits as an excuse to go even faster. But Michigan transportation
officials are encouraged by the results of boosting the speed limit on
Interstate 69 near Flint to 70 mph last August. When the speed limit
was 55 mph, about 1.8% of all vehicles zipped along at more than 80
mph. That fell to 1% after the change.
July 20, 2006
tadchem
Corey
You, me, and the Cabal, m8.
pst..
(I'm A Wizard)
tadchem
I was afraid for a moment that you might be referring to the collective
group of voices only you hear.
Tom Davidson
Richmond, VA
Cranks Reply
Corey wrote:
> tadchem wrote:
> > Corey...@gmail.com wrote:
> > <snip>
> >
> > What do you mean by "we"?
> >
> > Tom Davidson
> > Richmond, VA
"there is no we"
> You, me, and the Cabal, m8.
> pst..
> (I'm A Wizard)
you are a frigging retard. you couldnt wizard you way out of a paper
bag. the school holidays must be a fricking boring time for you. when
you get older you may even be able to start dating. but only if you
lose the wizard madness.
do you take any medication? if not, consider it a good idea.
Y.Porat
Hi disturbed nazi shit bum parasite
Y.P
--------------------------
Corey
I know people who say they are wizards often have a bad reputation, but
that doesn't mean witchcraft doesn't exist Mr. I am very lonely, that
much is true. But friendship is an illusion. We live in a capatalist
society, and the family unit is all disfuctional. Friendship is more
like saying comrad in english these days. And if you don't watch it I
might turn you into a toad, k buddy?
T Wake
"Corey" <Corey...@gmail.com> wrote in message
news:1153499117.2...@i3g2000cwc.googlegroups.com...
>
> I know people who say they are wizards often have a bad reputation, but
> that doesn't mean witchcraft doesn't exist Mr.
No, the fact it doesnt exist means that. The bad reputation is a side line.
> I am very lonely, that
> much is true.
I cant think why...
> But friendship is an illusion.
To you maybe. When you get over puberty you will learn to think otherwise.
> We live in a capatalist
> society, and the family unit is all disfuctional.
Again, there is more to life than your personal experiences.
> Friendship is more
> like saying comrad in english these days.
Whatever.
> And if you don't watch it I
> might turn you into a toad, k buddy?
Go one. Bet you cant turn me into a toad. Seriously, like last time you had
some school holidays and turned up here (under four or five different
names), you really need to grow up. Sadly this wont happen over night, but
one day you will reach puberty, then when you get past it and realise what
being an adult is like you will look at life differently. (Sadly, you will
probably regret being a jerk and wasting your youth more than anything else
but, hey, nevermind).
Lloyd Parker
Corey...@gmail.com wrote:
>
>States Boost Speed Limits On Major Highways
>Moves Come Despite Concerns Over Safety, High Gas Prices; 80 Miles Per
>Hour in Texas
And you spammed this to sci.environment why?
Corey...@gmail.com
It is more on topic than these global warming lunatics. The case for
global warming is rather thin, and it isn't going to create drastic
climate change until after we run out of fossil fuels. So conserving
our use of oil at a time like this, is even more important. Especially
because it isn't a renewable resource and we have already tapped out
most of the oil in the world. And obviously gas prices are high right
now anyway.
Why do you think it is off-topic?
T Wake
<Corey...@gmail.com> wrote in message
news:1153508763....@s13g2000cwa.googlegroups.com...
Don't your magician skills give you the answer?
Corey...@gmail.com
That's just your way of saying "ribbit" isn't it?
Now why don't you go and *croak*
rip...@azonic.co.nz
ji...@specsol.spam.sux.com wrote:
> The force required to maintain a given speed is equal to the drag
> at that speed.
Correct. But there is rolling drag (ie the drag from the tires, gears
etc) and aerodynamic drag.
> Drag is directly related to speed.
Drag is related to speed, but it is roughly the square of the speed.
Your use of 'directly' implies that you mistakenly think it is linear.
At 60 mph the drag is roughly 4 times that of 30 mph. Therefore, all
else being equal, the fuel use rate will be 4 times, while the time
taken is roughly half. Therefore at 60 the mpg is half that at 30 (all
else being equal).
> The efficiency of an internal combustion engine is a curve with a peak
> at some rpm. Speed and rpm are directly related by the transmission
> gear ratio, the axle gear ratio, and the size of the tires.
The efficiency may change somewhat, a few percent, but this is
insignificant compared to the change in drag as the speed increases.
T Wake
<Corey...@gmail.com> wrote in message
news:1153512338.8...@h48g2000cwc.googlegroups.com...
Oh sorry, I wasn't paying attention. Was that supposed to be a witty
comeback?
Are you still looking forward to puberty?
rip...@azonic.co.nz
Roy. Just Roy. wrote:
> That's one solution. Another solution is to reduce the weight that is
> rolled. A motorcycle will get 10X the MPG as an SUV, from sheer weight
> difference alone.
No. That is not true, it is not from 'sheer weight difference'. The
aerodynamic drag is realted to the frontal area and to the shape.
While a motorcycle may have a poor shape it has a very much smaller
frontal area. The box shape of an SUV doesn't help it either.
The rolling resistence _is_ related to the weight, but this is only one
factor.
rip...@azonic.co.nz
Corey...@gmail.com wrote:
> However look at my figuring:
> An average car weighs 1500 kg
> 1 meters = 0.000621371192 miles
> 55mph = 24.5872 meters / second ^2
>
> So the force at 55mph is 36880 newtons
You are confused. That is the force required to _accelerate_ the car
from zero to 55mph (without taking drag into account).
The force required to maintain the speed of 55mph on a flat road is
completely different and is the sum of the rolling resistence and the
aerodynamic drag, neither of which can be 'calculated'.
> But at 20 mph we see it differently: 8.94 meters / second ^2
> And the force is 13410 newtons
>
> So The work is less than half going at 20mph!!!!
Given that you are not calculating the correct things then your
conclusion is irrelevant.
rip...@azonic.co.nz
Randy Poe wrote:
> My recollection is that at the time, the universal justification given
> was that 55 mph was known to be the most efficient speed for
> a car, and that there were plenty of graphs being bandied about
> showing efficiency dropping off rapidly above 55 mph.
You are confused. Certainly above 55 the 'efficiency drops off
rapidly' as the drag increases at the square of the speed, but that
does not mean that 55 is 'the most efficient speed', it only means that
it has not 'dropped rapidily' below that of some slower speed.
When journey time is taken as a factor and given some dollar value then
the cost of a journey is fuel use + time taken. _THEN_ 55 or 60 is the
'most efficient' even if it uses more fuel than some slower speed.
ji...@specsol.spam.sux.com
> ji...@specsol.spam.sux.com wrote:
> > The force required to maintain a given speed is equal to the drag
> > at that speed.
> Correct. But there is rolling drag (ie the drag from the tires, gears
> etc) and aerodynamic drag.
Of course, but at highway speed, decent tires, and everything proper,
aerodynamic drag dominates.
> > Drag is directly related to speed.
> Drag is related to speed, but it is roughly the square of the speed.
> Your use of 'directly' implies that you mistakenly think it is linear.
No, I don't.
The use of directly implies drag goes up as speed goes up and says
nothing else about the relating function.
> At 60 mph the drag is roughly 4 times that of 30 mph. Therefore, all
> else being equal, the fuel use rate will be 4 times, while the time
> taken is roughly half. Therefore at 60 the mpg is half that at 30 (all
> else being equal).
Except the statement is totally false and based on overly simplified
assumptions.
To start, fuel flow in a vehicle is not a linear function of speed,
even if you make the assumption that it is measured at a constant
gear ratio.
> > The efficiency of an internal combustion engine is a curve with a peak
> > at some rpm. Speed and rpm are directly related by the transmission
> > gear ratio, the axle gear ratio, and the size of the tires.
> The efficiency may change somewhat, a few percent, but this is
> insignificant compared to the change in drag as the speed increases.
Utter nonsense and easily disproved.
I will state it again, every vehicle I have ever owned got it's best mpg
somewhere between about 50 and 80 mph.
--
Jim Pennino
Remove .spam.sux to reply.
ji...@specsol.spam.sux.com
> Corey...@gmail.com wrote:
> > However look at my figuring:
> > An average car weighs 1500 kg
> > 1 meters = 0.000621371192 miles
> > 55mph = 24.5872 meters / second ^2
> >
> > So the force at 55mph is 36880 newtons
> You are confused. That is the force required to _accelerate_ the car
> from zero to 55mph (without taking drag into account).
Quite true.
> The force required to maintain the speed of 55mph on a flat road is
> completely different and is the sum of the rolling resistence and the
> aerodynamic drag, neither of which can be 'calculated'.
But it is easily measured.
Find a flat spot, get to some speed, put the car in neutral to
elimate compression breaking, and time how long it takes the
speed to drop in some convienient increament such as 10 MPH
and plot the results.
Given the vehicle weight it becomes rather trivial to put numbers
on the drags.
> > But at 20 mph we see it differently: 8.94 meters / second ^2
> > And the force is 13410 newtons
> >
> > So The work is less than half going at 20mph!!!!
> Given that you are not calculating the correct things then your
> conclusion is irrelevant.
True again.
ji...@specsol.spam.sux.com
> Randy Poe wrote:
Therefor the 'most efficient' speed would be c minus a tad?
rip...@azonic.co.nz
ji...@specsol.spam.sux.com wrote:
> > When journey time is taken as a factor and given some dollar value then
> > the cost of a journey is fuel use + time taken. _THEN_ 55 or 60 is the
> > 'most efficient' even if it uses more fuel than some slower speed.
>
> Therefor the 'most efficient' speed would be c minus a tad?
Only if fuel were free and your time was infinitely valuable.
It would also help if there was a device that would scrape you from the
bulkhead after the acceleration.
ji...@specsol.spam.sux.com
> ji...@specsol.spam.sux.com wrote:
> > > When journey time is taken as a factor and given some dollar value then
> > > the cost of a journey is fuel use + time taken. _THEN_ 55 or 60 is the
> > > 'most efficient' even if it uses more fuel than some slower speed.
> >
> > Therefor the 'most efficient' speed would be c minus a tad?
> Only if fuel were free and your time was infinitely valuable.
So your statement that "...is the 'most efficient' even if it uses more
fuel than some slower speed." is false, true, or sometimes true and
sometimes false?
> It would also help if there was a device that would scrape you from the
> bulkhead after the acceleration.
The acceleration is 1.125G.
Next comment.
Randy Poe
rip...@Azonic.co.nz wrote:
> Randy Poe wrote:
>
> > My recollection is that at the time, the universal justification given
> > was that 55 mph was known to be the most efficient speed for
> > a car, and that there were plenty of graphs being bandied about
> > showing efficiency dropping off rapidly above 55 mph.
>
> You are confused.
About what was said in the 1970s?
> Certainly above 55 the 'efficiency drops off
> rapidly' as the drag increases at the square of the speed, but that
> does not mean that 55 is 'the most efficient speed', it only means that
> it has not 'dropped rapidily' below that of some slower speed.
I'm not weighing in one way or another about whether it's true,
I'm just reporting what the justification for 55 mph was.
As I recall.
- Randy
rip...@azonic.co.nz
ji...@specsol.spam.sux.com wrote:
> Of course, but at highway speed, decent tires, and everything proper,
> aerodynamic drag dominates.
Correct.
> The use of directly implies drag goes up as speed goes up and says
> nothing else about the relating function.
Other factors also affect the drag: opening or closing windows, road
surface, wind. So drag is not directly the result of the speed.
> > At 60 mph the drag is roughly 4 times that of 30 mph. Therefore, all
> > else being equal, the fuel use rate will be 4 times, while the time
> > taken is roughly half. Therefore at 60 the mpg is half that at 30 (all
> > else being equal).
>
> Except the statement is totally false and based on overly simplified
> assumptions.
The aerodynamic drag increases as a function that is the square of the
speed for speeds that are around those found on roads and the highways,
ie from 30 to 60.
> To start, fuel flow in a vehicle is not a linear function of speed,
> even if you make the assumption that it is measured at a constant
> gear ratio.
No, it is not linear, it increases faster than that.
> Utter nonsense and easily disproved.
>
> I will state it again, every vehicle I have ever owned got it's best mpg
> somewhere between about 50 and 80 mph.
Than you must have magic vehicles. Or possibly your driving habits are
particularly poor. When actual measurements are done (rather than mere
unsupported claims) the results are like this:
http://www.gassavers.org/showthread.php?t=980
Note that while the graph is marked as 'mph' it is actually kph. You
should note that from 30 mph (50kph) to 60 mph (100kph) the mpg falls
by roughly half (26.x to 16mpg or 53 to 25) even on the best (except
the Prius). This indicates that fuel flow has increased by around to 4
fold which is exactly what my claim was - backed by actual tests.
So what actual test results can you show to attempt to prove your claim
of magic ?
rip...@azonic.co.nz
Randy Poe wrote:
> > > My recollection is that at the time, the universal justification given
> > > was that 55 mph was known to be the most efficient speed for
> > > a car, and that there were plenty of graphs being bandied about
> > > showing efficiency dropping off rapidly above 55 mph.
> >
> > You are confused.
>
> About what was said in the 1970s?
>
> I'm not weighing in one way or another about whether it's true,
> I'm just reporting what the justification for 55 mph was.
You are confused that 'most efficient' was used to mean 'least fuel
usage'.
For example it may have referred to the fact that the speed was 'most
efficient' use of the road. Faster speeds require larger spacing
between cars meaning there must be fewer cars on the road. Less speed
means that cars are on the road for a longer time, thus there are more
cars on the road at any given time.
For speeds faster or slower than 55 mph for a given traffic loading
there would need to be more lanes. Thus 55 is the 'most efficient'.
Nothing to do with fuel economy at all.
Alternately it may be 'most efficient' when fuel usage, time, and
accident rates are also taken into account.
55 mph is certaily not the point for any car to give the most mpg.
R Philip Dowds
Eh? Fossil fuel combustion is all about putting massive amounts of
carbon, formerly sequestered in the ground for hundreds of thousands of
years, back into the atmosphere from whence it came. Anthropogenic
global warming is all about the CO2 we put back in the atmosphere
restoring our planetary climate to what it was one or two billion years
ago. So ... how is it that climate change cannot occur until *after*
we've burned up all the fossil fuels?
You seem to adhere to some theory of non-cause and anti-effect that is
unfamiliar to me.
RPD / Cambridge
Facts can be your friends if you treat them right.
ji...@specsol.spam.sux.com
> rip...@Azonic.co.nz wrote:
> > Randy Poe wrote:
> >
> > > My recollection is that at the time, the universal justification given
> > > was that 55 mph was known to be the most efficient speed for
> > > a car, and that there were plenty of graphs being bandied about
> > > showing efficiency dropping off rapidly above 55 mph.
> >
> > You are confused.
> About what was said in the 1970s?
You are correct.
The official line was going from 65 mph to 55 mph resulted in higher
mpg.
It may well have been true for the older klunkers from the 60's on the
road at the time, but it certainly wasn't absolutely true.
At the time the 55 law passed, I was doing lots of long distance
driving in a new Toyota and gas was a major expense.
From experiment, I determined I got the best mileage at 70 MPH (data
to the nearest 5 MPH) and was really steamed when my gas usage went up
to "save gas" by federal mandate.
<snip remaining>
rip...@azonic.co.nz
ji...@specsol.spam.sux.com wrote:
> > > > When journey time is taken as a factor and given some dollar value then
> > > > the cost of a journey is fuel use + time taken. _THEN_ 55 or 60 is the
> > > > 'most efficient' even if it uses more fuel than some slower speed.
> > >
> > > Therefor the 'most efficient' speed would be c minus a tad?
>
> > Only if fuel were free and your time was infinitely valuable.
>
> So your statement that "...is the 'most efficient' even if it uses more
> fuel than some slower speed." is false, true, or sometimes true and
> sometimes false?
Exactly, depending entirely on cost of fuel and what number is given to
the value for your time. Given a particular fuel cost and a particular
"some dollar value" for the time then 55 or 60 is the 'most efficient'.
If your time is worth $1.00 per year then journey time is almost
irrelevant and the 'most efficient' is some slow speed that uses
minimum fuel. If your time is worth $10,000.00 per hour then
chartering a private jet to go to the local shop may be the 'most
efficient'.
At 'a tad less than c' the time (for the traveller) is nearly zero for
any long journey so regardless of any _finite_ value of your time it is
never 'the most efficient'.
> > It would also help if there was a device that would scrape you from the
> > bulkhead after the acceleration.
>
> The acceleration is 1.125G.
Then the total journey is very much less than 'c minus a tad'.
rip...@azonic.co.nz
ji...@specsol.spam.sux.com wrote:
> At the time the 55 law passed, I was doing lots of long distance
> driving in a new Toyota and gas was a major expense.
>
> From experiment, I determined I got the best mileage at 70 MPH (data
> to the nearest 5 MPH) and was really steamed when my gas usage went up
> to "save gas" by federal mandate.
It may well be true that on journeys that you were able to cruise at
70mph you used less fuel than on journeys where you were not able to
keep up such speeds.
Acceleration is a major user of fuel. It takes more fuel to accerate
from 50 to 60 than it does to maintain a speed of 60. If you were able
to keep up a speed of 70 then this implies that there was little
traffic and no requirement to brake and accelerate. Journeys with
slower average speeds may be because you had to slow down and
accelerate thus using more fuel.
But your claim is that your car uses less fuel to travel 1 mile at a
steady 70mph then it does at 55mph.
This claim is in conflict will all known laws of physics and from all
impirical testing done. Or perhaps your transmission was broken and
stayed in a lower gear at 55mph.
ji...@specsol.spam.sux.com
> ji...@specsol.spam.sux.com wrote:
> > At the time the 55 law passed, I was doing lots of long distance
> > driving in a new Toyota and gas was a major expense.
> >
> > From experiment, I determined I got the best mileage at 70 MPH (data
> > to the nearest 5 MPH) and was really steamed when my gas usage went up
> > to "save gas" by federal mandate.
> It may well be true that on journeys that you were able to cruise at
> 70mph you used less fuel than on journeys where you were not able to
> keep up such speeds.
It is true and repeatedly varified. The "not able to keep up" is
irrelevant crap. Going 55 mph on these trips before the 55 mph
speed limit would have been suicide.
> Acceleration is a major user of fuel. It takes more fuel to accerate
> from 50 to 60 than it does to maintain a speed of 60. If you were able
> to keep up a speed of 70 then this implies that there was little
> traffic and no requirement to brake and accelerate. Journeys with
> slower average speeds may be because you had to slow down and
> accelerate thus using more fuel.
You sure are good at throwing out irrelevant crap.
These were trips of hundreds of miles, on the open highway, maintaining
a steady cruise speed.
There was insignificant acceleration or deceleration, I didn't roll
the windows up and down, open the doors, or drag an anvil on a chain.
There were multiple trips at each speed.
> But your claim is that your car uses less fuel to travel 1 mile at a
> steady 70mph then it does at 55mph.
Yep, but to be precise, that car. That car was about 10 cars ago.
> This claim is in conflict will all known laws of physics and from all
> impirical testing done. Or perhaps your transmission was broken and
> stayed in a lower gear at 55mph.
More irrelevant crap; it had a manual transmission.
The claim is based on experimental data.
rip...@azonic.co.nz
ji...@specsol.spam.sux.com wrote:
> > This claim is in conflict will all known laws of physics and from all
> > impirical testing done. Or perhaps your transmission was broken and
> > stayed in a lower gear at 55mph.
>
> More irrelevant crap; it had a manual transmission.
>
> The claim is based on experimental data.
Which you have not provided.
Experimental data, which is substancial, for a wide variety of vehicles
and done in controlled conditions and for which the methodology is
recorded, show the exact opposite of your claim.
Here is an example that I have no reason to disbelieve:
http://images6.theimagehosting.com/mpg-vs-speed-chart.371.gif
Your claim is that from 55 to 70 the curve for yoiur car would be
upwards. That is not believable.
ji...@specsol.spam.sux.com
> ji...@specsol.spam.sux.com wrote:
> > > This claim is in conflict will all known laws of physics and from all
> > > impirical testing done. Or perhaps your transmission was broken and
> > > stayed in a lower gear at 55mph.
> >
> > More irrelevant crap; it had a manual transmission.
> >
> > The claim is based on experimental data.
> Which you have not provided.
Let's see, this is 2006, we are talking about the early 1970's...
*It was over thirty years ago.*
> Experimental data, which is substancial, for a wide variety of vehicles
> and done in controlled conditions and for which the methodology is
> recorded, show the exact opposite of your claim.
> Here is an example that I have no reason to disbelieve:
> http://images6.theimagehosting.com/mpg-vs-speed-chart.371.gif
> Your claim is that from 55 to 70 the curve for yoiur car would be
> upwards. That is not believable.
Did you happen to notice that all those curves are for cars with
really tiny engines?
rip...@azonic.co.nz
ji...@specsol.spam.sux.com wrote:
> Let's see, this is 2006, we are talking about the early 1970's...
Was it, that is strange, you had written:
"""Of the cars I've owned, the lowest speed best mileage was about 60
MPH
and the highest was about 80 MPH.
The car I currently own seems to like a tad under 70 MPH."""
"""I will state it again, every vehicle I have ever owned got it's best
mpg
somewhere between about 50 and 80 mph."""
> *It was over thirty years ago.*
Your claim seems to span all of the last 30 years so what is your
actual point ?
> > Your claim is that from 55 to 70 the curve for yoiur car would be
> > upwards. That is not believable.
>
> Did you happen to notice that all those curves are for cars with
> really tiny engines?
Well, actually, no, I did not. But then I don't consider Mercedes and
BMWs to be 'really tiny engines', a 3.5 litre twin turbo, nor even the
two litres, are hardly 'really tiny'. The first reference are mostly
performance cars.
"""At the time the 55 law passed, I was doing lots of long distance
driving in a new Toyota and gas was a major expense. """
Toyotas are not generally known for having large engines.
Every car that has been scientifically measured (except the Prius)
shows the exact consumption curves from 30mph to 80mph predicted by
theory that drag increases at the square of the speed and fuel usage
increases to provide the energy to overcome this drag.
Your claim is that somehow all your cars demonstrate magic by ignoring
provable scientific laws.
Either your driving is complete crap or your experimental methodology
is, or both.
Lloyd Parker
Corey...@gmail.com wrote:
>
>Lloyd Parker wrote:
>> In article <1153434339....@m73g2000cwd.googlegroups.com>,
>> Corey...@gmail.com wrote:
>> >
>> >States Boost Speed Limits On Major Highways
>> >Moves Come Despite Concerns Over Safety, High Gas Prices; 80 Miles Per
>> >Hour in Texas
>>
>> And you spammed this to sci.environment why?
>
>It is more on topic than these global warming lunatics.
Huh? GW is an environmental issue; you getting in the WSJ is just ego.
>The case for
>global warming is rather thin,
OK, now I can see why you posted your spam. YOU'RE AN IDIOT!
>and it isn't going to create drastic
>climate change until after we run out of fossil fuels. So conserving
>our use of oil at a time like this, is even more important. Especially
>because it isn't a renewable resource and we have already tapped out
>most of the oil in the world. And obviously gas prices are high right
>now anyway.
>
>Why do you think it is off-topic?
>
Explain how you getting in the WSJ is a science or environmental issue.
Ian Parker
I believe that road safety should be the main reason for the imposition
of a speed limit. Smooth flow of traffic (viz variable limits) shouls
be the other part of the reason. Energy efficiency not at all! I say
this for 2 reasons.
1) You will not save the world by driving at 90km/h. The world can only
be saved by NEW TECHNOLOGY. In fact if we dove ast 130km/h (83mph) car
design would improve and C/D figures improve. Also driving at 90km/h
sends the message that there is nothing that can be done
technologically to increase energy resources or to cool the planet.
Neither of these is true. The true short/medium answer is Nuclear
Power, with solar energy and either the electrolysis of water using
phtovoltaics, or direct production of hydrogen by a phtosynthetic
process. Labor is cheaper in Mexico (where there is a lot of desert).
Perhaps mirrors could be assembled there.
2) Where do you stop? The Police can check your speed FOR REASONS OF
ROAD SAFETY. If you allow them to check it for energy efficiency where
do you end? Do you allow them to carry thermal imagers and go into your
own home, iof they suspect you have set your thermostat inappropriately?
Ian Parker
have Nuclear Power. If has in fact been shown that low doses of
radiation do not follow a linear curve. In fact cells have a repair
mechanism.
In fact driving at 90km/h and other aspects of gesture politics have
directly led to the Middle East situation c'mon oil finances Hezbullah
and Iran.