Awl --

Are two cars hitting each other at 50 mph the same as 1 car hitting an
immovable wall at 100 mph?
As nauseous as those two make me, along with that dreadful gerl., they did a
good job on tonites show.
Title: Mythssion Control: The fans take control.

A variety of neat **** for metal heads.
They "solved" the problem early on, using pendulums, inneresting in itself,
but goddamm, you gotta see the diff between cars hitting walls at 50 and 100
mph, when they used actual cars. In an Arizona test facility, very
inneresting unto itself.

Be prepared, tho, they spread this thing over the whole goddamm hour....
figgers.
Which is rough on me, cuz after more than 15 minutes with those two
assholes, I have to take the wife's motion sickness pills to keep my food
down.

--
EA

Existential Angst wrote:
Awl --

Are two cars hitting each other at 50 mph the same as 1 car hitting an
immovable wall at 100 mph?
As nauseous as those two make me, along with that dreadful gerl., they did a
good job on tonites show.
Title: Mythssion Control: The fans take control.

A variety of neat **** for metal heads.
They "solved" the problem early on, using pendulums, inneresting in itself,
but goddamm, you gotta see the diff between cars hitting walls at 50 and 100
mph, when they used actual cars. In an Arizona test facility, very
inneresting unto itself.

Be prepared, tho, they spread this thing over the whole goddamm hour....
figgers.
Which is rough on me, cuz after more than 15 minutes with those two
assholes, I have to take the wife's motion sickness pills to keep my food
down.


Race car driver David Purley survived an estimated 179.8 G's in 1977
when he decelerated from 173 km/h (108 mph) to 0 in a distance of 66 cm
(26 inches) after his throttle got stuck wide open and he hit a wall.

http://en.wikipedia.org/wiki/David_Purley

Beryl writes:

Existential Angst wrote:
Awl --

Are two cars hitting each other at 50 mph the same as 1 car hitting
an immovable wall at 100 mph?
As nauseous as those two make me, along with that dreadful gerl.,
they did a good job on tonites show.
Title: Mythssion Control: The fans take control.

A variety of neat **** for metal heads.
They "solved" the problem early on, using pendulums, inneresting in
itself, but goddamm, you gotta see the diff between cars hitting
walls at 50 and 100 mph, when they used actual cars. In an Arizona
test facility, very inneresting unto itself.

Be prepared, tho, they spread this thing over the whole goddamm
hour.... figgers.
Which is rough on me, cuz after more than 15 minutes with those two
assholes, I have to take the wife's motion sickness pills to keep my
food down.


Race car driver David Purley survived an estimated 179.8 G's in 1977
when he decelerated from 173 km/h (108 mph) to 0 in a distance of 66
cm (26 inches) after his throttle got stuck wide open and he hit a
wall.

http://en.wikipedia.org/wiki/David_Purley

And went on to die doing aerobatics...
--
As we enjoy great advantages from the inventions of others, we should
be glad of an opportunity to serve others by any invention of ours;
and this we should do freely and generously. (Benjamin Franklin)

"Existential Angst" wrote in message
...
Awl --

Are two cars hitting each other at 50 mph the same as 1 car hitting an
immovable wall at 100 mph?

Short answer = no.

Longer answer. If the 2 cars are the same mass(weight) they will both
come to a stop at the point of the collision. Now imagine a brick wall
at that point and each car slams into a side. Each car goes from 50mph
to zero in both cases.

Now only use 1 car and the brick wall. That car still goes from 50mph
to 0mph.

In terms of physics each car has energy = 1/2mv^2, where m = mass
and v= velocity. For 1 car going 50mph: 1/2m(50)^2 = 1250m units
The total energy for both cars is 2500m units.
For 1 car going 100mph its energy is 1/2m(100)^2 = 5000m units.
Clearly not the same thing.
Art

"Artemus" wrote in message
...

"Existential Angst" wrote in message
...
Awl --

Are two cars hitting each other at 50 mph the same as 1 car hitting an
immovable wall at 100 mph?

Short answer = no.

Longer answer. If the 2 cars are the same mass(weight) they will both
come to a stop at the point of the collision. Now imagine a brick wall
at that point and each car slams into a side. Each car goes from 50mph
to zero in both cases.

Now only use 1 car and the brick wall. That car still goes from 50mph
to 0mph.

In terms of physics each car has energy = 1/2mv^2, where m = mass
and v= velocity. For 1 car going 50mph: 1/2m(50)^2 = 1250m units
The total energy for both cars is 2500m units.
For 1 car going 100mph its energy is 1/2m(100)^2 = 5000m units.
Clearly not the same thing.
Art

Right on Art. This (two cars doing 50 same as one car hitting wall at 100)
is a myth that has to be dispelled.
I have given up trying to set this right when it comes up in social
settings. Isn't worth the effort. Of course, in technical or engineering
settings the subject doesn't even come up because they all know the right
answer.
It's the media that feeds this falsehood.

Ivan Vegvary

On 5/5/2010 10:50 PM, Ivan Vegvary wrote:

"Artemus" wrote in message
...

"Existential Angst" wrote in message
...
Awl --
Are two cars hitting each other at 50 mph the same as 1 car hitting an
immovable wall at 100 mph?

Short answer = no.

Longer answer. If the 2 cars are the same mass(weight) they will both
come to a stop at the point of the collision. Now imagine a brick wall
at that point and each car slams into a side. Each car goes from 50mph
to zero in both cases.

Now only use 1 car and the brick wall. That car still goes from 50mph
to 0mph.

In terms of physics each car has energy = 1/2mv^2, where m = mass
and v= velocity. For 1 car going 50mph: 1/2m(50)^2 = 1250m units
The total energy for both cars is 2500m units.
For 1 car going 100mph its energy is 1/2m(100)^2 = 5000m units.
Clearly not the same thing.
Art

Right on Art. This (two cars doing 50 same as one car hitting wall at
100) is a myth that has to be dispelled.
I have given up trying to set this right when it comes up in social
settings. Isn't worth the effort. Of course, in technical or engineering
settings the subject doesn't even come up because they all know the
right answer.
It's the media that feeds this falsehood.

Ivan Vegvary

Not just the media but in California the DMV in their driver's license
booklet perpetrates the myth, but what can one expect from a government
agency...

cheers
T.Alan

Einstein's E = MC (squared).

Inverse square law has to do with propagation of light from
a point source.

--
Christopher A. Young
Learn more about Jesus
www.lds.org
..


"John R. Carroll" wrote in message
...
Interesting to contemplate- if one car at 50 has energy X,
2 cars
going 50 has 2X, but one car going 100 has 4X.

I'd expect equivalence at 1.414x50 mph, or 70.7mph.


Inverse square law.


--
John R. Carroll

Stormin Mormon wrote:
Einstein's E = MC (squared).

Inverse square law has to do with propagation of light from
a point source.

Lots of things have inverse square relationships. In this case:
Force equals the one half the Mass X the Square of the Velocity so if you
reduce the Velocity by half you get ?

It's early here. I'm on my first cup.
LOL

--
John R. Carroll

On Wed, 5 May 2010 21:34:52 -0700, "Artemus" wrote
the following:


"Existential Angst" wrote in message
...
Awl --

Are two cars hitting each other at 50 mph the same as 1 car hitting an
immovable wall at 100 mph?

Short answer = no.

Longer answer. If the 2 cars are the same mass(weight) they will both
come to a stop at the point of the collision. Now imagine a brick wall
at that point and each car slams into a side. Each car goes from 50mph
to zero in both cases.

Now only use 1 car and the brick wall. That car still goes from 50mph
to 0mph.

In terms of physics each car has energy = 1/2mv^2, where m = mass
and v= velocity. For 1 car going 50mph: 1/2m(50)^2 = 1250m units
The total energy for both cars is 2500m units.
For 1 car going 100mph its energy is 1/2m(100)^2 = 5000m units.
Clearly not the same thing.
Art

Close, but no cigar, since you assumed vehicles of equal mass. If you
have a Chebby Geo meet a Suburban, it will be closer to 75mph Geo vs
25mph Suburban. The doubled mass of the heavier vehicle will keep
pushing until it shoves the Geo a wee bit more. You'd definitely
rather be an occupant in the larger, heavier vehicle.

Sister Mary Elizabeth says "ClaaaaaaaaaaAss!"
This is demonstrable in a vise. Chuck a sheet of 1/4" steel in it and
get a common ball peen hammer on one side and a 3# sledge on the
other. Hold the sledge against the strip of steel and hit the other
side with the ball peen. Reaction: small movement of the sledge. Now
hold the ball peen against the steel and hit it with the sledge.
Reaction: The ball peen hammer goes flying.

--
All national institutions of churches, whether Jewish, Christian,
or Turkish, appear to me no other than human inventions, set up
to terrify and enslave mankind, and monopolize power and profit.
--Thomas Paine

Larry Jaques wrote:
On Wed, 5 May 2010 21:34:52 -0700, "Artemus" wrote
the following:


"Existential Angst" wrote in message
...
Awl --

Are two cars hitting each other at 50 mph the same as 1 car hitting
an immovable wall at 100 mph?

Short answer = no.

Longer answer. If the 2 cars are the same mass(weight) they will
both come to a stop at the point of the collision. Now imagine a
brick wall at that point and each car slams into a side. Each car
goes from 50mph to zero in both cases.

Now only use 1 car and the brick wall. That car still goes from
50mph to 0mph.

In terms of physics each car has energy = 1/2mv^2, where m = mass
and v= velocity. For 1 car going 50mph: 1/2m(50)^2 = 1250m units
The total energy for both cars is 2500m units.
For 1 car going 100mph its energy is 1/2m(100)^2 = 5000m units.
Clearly not the same thing.
Art

Close, but no cigar, since you assumed vehicles of equal mass. If you
have a Chebby Geo meet a Suburban, it will be closer to 75mph Geo vs
25mph Suburban. The doubled mass of the heavier vehicle will keep
pushing until it shoves the Geo a wee bit more. You'd definitely
rather be an occupant in the larger, heavier vehicle.

Sister Mary Elizabeth says "ClaaaaaaaaaaAss!"
This is demonstrable in a vise. Chuck a sheet of 1/4" steel in it and
get a common ball peen hammer on one side and a 3# sledge on the
other. Hold the sledge against the strip of steel and hit the other
side with the ball peen. Reaction: small movement of the sledge. Now
hold the ball peen against the steel and hit it with the sledge.
Reaction: The ball peen hammer goes flying.

Yeah but since you are varying the mass, the relationship is linear.


--
John R. Carroll

In article , lid wrote:

Close, but no cigar, since you assumed vehicles of equal mass. If you
have a Chebby Geo meet a Suburban, it will be closer to 75mph Geo vs
25mph Suburban. The doubled mass of the heavier vehicle will keep
pushing until it shoves the Geo a wee bit more. You'd definitely
rather be an occupant in the larger, heavier vehicle.

That's not the only, or even most important, factor...

Years ago, there was a fatal collision on the state highway about a mile from
our house. A Chevette crossed the yellow line and collided head-on with a
full-size pickup truck, each going some 50mph. The **seat belted** driver of
the Chevette had a broken ankle. The **unbelted** driver of the truck and his
unbelted passenger died at the scene.

"Doug Miller" wrote in message
...
In article ,
lid wrote:

Close, but no cigar, since you assumed vehicles of equal mass. If you
have a Chebby Geo meet a Suburban, it will be closer to 75mph Geo vs
25mph Suburban. The doubled mass of the heavier vehicle will keep
pushing until it shoves the Geo a wee bit more. You'd definitely
rather be an occupant in the larger, heavier vehicle.

That's not the only, or even most important, factor...

Years ago, there was a fatal collision on the state highway about a mile
from
our house. A Chevette crossed the yellow line and collided head-on with a
full-size pickup truck, each going some 50mph. The **seat belted** driver
of
the Chevette had a broken ankle. The **unbelted** driver of the truck and
his
unbelted passenger died at the scene.

That sounds like my collision in January, 1971. I was in a '67 Bronco, with
seatbelt (but there was no shoulder harness in the car). The other car was a
Pontiac Tempest with a man and his young daughter in the front seat, no
seatbelts.

We collided head-on at around 40 mph (me) and maybe 30 mph (them). The girl
required extensive surgery to her face. The man had a ruptured spleen but he
lived. I hit the steering wheel and twisted it into a pretzel, but I just
wound up with a cut on my chin and bled all over my new Abercrombie & Fitch
sheepskin coat. I was able to jump out, check on them, and run to a nearby
house to call the ambulance.

--
Ed Huntress

Larry Jaques wrote:

Close, but no cigar, since you assumed vehicles of equal mass. If you
have a Chebby Geo meet a Suburban, it will be closer to 75mph Geo vs
25mph Suburban. The doubled mass of the heavier vehicle will keep
pushing until it shoves the Geo a wee bit more. You'd definitely
rather be an occupant in the larger, heavier vehicle.

Only if you are committed to a collision and have
no other options. Otherwise I'd prefer a agile
vehicle with good braking and cornering performance.

And that would be neither a Suburban or a Geo.

I wonder sometimes, if the Mini Cooper, Yugo, and some of
the other feather weight cars. If they are going to lead to
more traffic fatalities?

--
Christopher A. Young
Learn more about Jesus
www.lds.org
..


"Larry Jaques" wrote in message
...

Close, but no cigar, since you assumed vehicles of equal
mass. If you
have a Chebby Geo meet a Suburban, it will be closer to
75mph Geo vs
25mph Suburban. The doubled mass of the heavier vehicle will
keep
pushing until it shoves the Geo a wee bit more. You'd
definitely
rather be an occupant in the larger, heavier vehicle.

Sister Mary Elizabeth says "ClaaaaaaaaaaAss!"
This is demonstrable in a vise. Chuck a sheet of 1/4" steel
in it and
get a common ball peen hammer on one side and a 3# sledge on
the
other. Hold the sledge against the strip of steel and hit
the other
side with the ball peen. Reaction: small movement of the
sledge. Now
hold the ball peen against the steel and hit it with the
sledge.
Reaction: The ball peen hammer goes flying.

--
All national institutions of churches, whether Jewish,
Christian,
or Turkish, appear to me no other than human inventions, set
up
to terrify and enslave mankind, and monopolize power and
profit.
--Thomas
Paine

Edward A. Falk wrote:
In article ,
Artemus wrote:
Are two cars hitting each other at 50 mph the same as 1 car hitting an
immovable wall at 100 mph?
Short answer = no.

Longer answer. If the 2 cars are the same mass(weight) they will both
come to a stop at the point of the collision. Now imagine a brick wall
at that point and each car slams into a side. Each car goes from 50mph
to zero in both cases.

Now only use 1 car and the brick wall. That car still goes from 50mph
to 0mph.

I never thought of it that way.

I'd guess that two cars hitting each other at 50 would be equivalent to
one car going 100 hitting another car that was sitting still in neutral
with no brakes.

The outcome also depends on how rigid the cars are, not only their
masses. Imagine both 50mph cars are billiard balls. They meet head-on
and accelerate not from 50 to 0, but from +50 to -50. About the same as
a "softer" car hitting a wall and going +100 to 0.

"Artemus" wrote in message
...

"Existential Angst" wrote in message
...
Awl --

Are two cars hitting each other at 50 mph the same as 1 car hitting an
immovable wall at 100 mph?

Short answer = no.

Longer answer. If the 2 cars are the same mass(weight) they will both
come to a stop at the point of the collision. Now imagine a brick wall
at that point and each car slams into a side. Each car goes from 50mph
to zero in both cases.

Now only use 1 car and the brick wall. That car still goes from 50mph
to 0mph.

In terms of physics each car has energy = 1/2mv^2, where m = mass
and v= velocity. For 1 car going 50mph: 1/2m(50)^2 = 1250m units
The total energy for both cars is 2500m units.
For 1 car going 100mph its energy is 1/2m(100)^2 = 5000m units.
Clearly not the same thing.
Art

I wrote the above before seeing the MB episode.
I have now watched it and am impressed with their experiment with actual
vehicles.

However, they have committed another glaring physics error. Anybody
else catch it too? Hint: it has to do with the clay & pendulum experiment.
Art

"Edward A. Falk" wrote in message
...
In article ,
Artemus wrote:

Are two cars hitting each other at 50 mph the same as 1 car hitting an
immovable wall at 100 mph?

Short answer = no.

Longer answer. If the 2 cars are the same mass(weight) they will both
come to a stop at the point of the collision. Now imagine a brick wall
at that point and each car slams into a side. Each car goes from 50mph
to zero in both cases.

Now only use 1 car and the brick wall. That car still goes from 50mph
to 0mph.

I never thought of it that way.

I'd guess that two cars hitting each other at 50 would be equivalent to
one car going 100 hitting another car that was sitting still in neutral
with no brakes.

That would be true at, and very shortly after, the moment of the collision.
Assuming equal weight cars - the moving car would go from 100 to 50mph
and the stationary car would go from 0 to 50mph. Both cars would sustain
essentially the same damage as if they were both going 50 to 0mph. Once
the collision was complete both cars would slow to 0mph due to friction
with the ground.
Art

"Larry Jaques" wrote in message
...
On Wed, 5 May 2010 21:34:52 -0700, "Artemus" wrote
the following:


"Existential Angst" wrote in message
...
Awl --

Are two cars hitting each other at 50 mph the same as 1 car hitting an
immovable wall at 100 mph?

Short answer = no.

Longer answer. If the 2 cars are the same mass(weight) they will both
come to a stop at the point of the collision. Now imagine a brick wall
at that point and each car slams into a side. Each car goes from 50mph
to zero in both cases.

Now only use 1 car and the brick wall. That car still goes from 50mph
to 0mph.

In terms of physics each car has energy = 1/2mv^2, where m = mass
and v= velocity. For 1 car going 50mph: 1/2m(50)^2 = 1250m units
The total energy for both cars is 2500m units.
For 1 car going 100mph its energy is 1/2m(100)^2 = 5000m units.
Clearly not the same thing.
Art

Close, but no cigar, since you assumed vehicles of equal mass. If you
have a Chebby Geo meet a Suburban, it will be closer to 75mph Geo vs
25mph Suburban. The doubled mass of the heavier vehicle will keep
pushing until it shoves the Geo a wee bit more. You'd definitely
rather be an occupant in the larger, heavier vehicle.

I did assume equal mass and stated that. As did the MB. Since you
reject my analysis are you rejecting theirs too?

You are right that vehicles of unequal mass will result in a different
outcome.
Art

How do you figure that the kinteic energy is half of MV^2?

--
Christopher A. Young
Learn more about Jesus
www.lds.org
..


"anorton" wrote in
message
m...


In Response to John: It is kinetic energy that equals 1/2
Mass X Velocity^2
Force is Mass X Acceleration (or de-acceleration in this
case). However, the
damage done to a car depends on both the energy and the
force and where it
is applied. When a car is stopped by brakes rather than a
brick wall, the
conversion of kinetic energy to heat is the same, but the
de-acceleration is
smaller, and thus the force is smaller and applied to a part
designed to
take it. The amount of damage depends on the energy
converted only while
the force is above a level required to break something. In
that case, the
kinetic energy is converted to first to bending the metal
and then to heat
as the metal is permanently bent. Some of the energy goes
into flying parts.

I've not seen the Myth Busters episode. However, I'd guess
their physics error is not observing mI = TA^2
(male Interest = Tits+Ass squared)

--
Christopher A. Young
Learn more about Jesus
www.lds.org
..


"Artemus" wrote in message
...

"Artemus" wrote in message
...

"Existential Angst" wrote in
message
...
Awl --

Are two cars hitting each other at 50 mph the same as 1
car hitting an
immovable wall at 100 mph?

Short answer = no.

Longer answer. If the 2 cars are the same mass(weight)
they will both
come to a stop at the point of the collision. Now imagine
a brick wall
at that point and each car slams into a side. Each car
goes from 50mph
to zero in both cases.

Now only use 1 car and the brick wall. That car still
goes from 50mph
to 0mph.

In terms of physics each car has energy = 1/2mv^2, where m
= mass
and v= velocity. For 1 car going 50mph: 1/2m(50)^2 =
1250m units
The total energy for both cars is 2500m units.
For 1 car going 100mph its energy is 1/2m(100)^2 = 5000m
units.
Clearly not the same thing.
Art

I wrote the above before seeing the MB episode.
I have now watched it and am impressed with their experiment
with actual
vehicles.

However, they have committed another glaring physics error.
Anybody
else catch it too? Hint: it has to do with the clay &
pendulum experiment.
Art

"Stormin Mormon" wrote in message
...
How do you figure that the kinteic energy is half of MV^2?

--
Christopher A. Young
Learn more about Jesus
www.lds.org
.


You learn it the first couple of weeks in high school physics:
http://en.wikipedia.org/wiki/Kinetic...f_rigid_bodies

On May 5, 10:09*pm, "Existential Angst"
wrote:
Awl --

Are two cars hitting each other at 50 mph the same as 1 car hitting an
immovable wall at 100 mph?
As nauseous as those two make me, along with that dreadful gerl., they did a
good job on tonites show.
Title: Mythssion Control: *The fans take control.

A variety of neat **** for metal heads.
They "solved" the problem early on, using pendulums, inneresting in itself,
but goddamm, you gotta see the diff between cars hitting walls at 50 and 100
mph, when they used actual cars. *In an Arizona test facility, very
inneresting unto itself.

Be prepared, tho, they spread this thing over the whole goddamm hour....
figgers.
Which is rough on me, cuz after more than 15 minutes with those two
assholes, I have to take the wife's motion sickness pills to keep my food
down.

--
EA

OK, The physics say it's not the same, but did they talk about closing
speed and reaction time? While you'd have plenty of time to say "Oh
****!" at 50 mph, you'd barely have time for "Oh sh" at 100.

Just sayin'

"Stormin Mormon" wrote in message
...
I've not seen the Myth Busters episode. However, I'd guess
their physics error is not observing mI = TA^2
(male Interest = Tits+Ass squared)

--
Christopher A. Young
Learn more about Jesus

In my physics class theorized that teats plus brains is a constant!

Ivan Vegvary

Stormin Mormon wrote:
And, it's in relationship to the sqare of the velocity,
which John Carrol and I have been agreeing.

I can't tell if you guys are making jokes along the lines of
the recent
Intel ads, or you just forgot your physics over the years.

In response to Christopher's posts: This has nothing to do
with Einstein
(unless cars are moving at 100,000 miles/second). It is all
Newton. In
E=MC2, C is specifically the speed of light, not the
velocity of the
object.


Iff V = C then F = E



--

Richard Lamb
http://www.home.earthlink.net/~cavelamb/

If I run that through a Street to Catholic translater
computer, would that come out as time for two Hail Marys,
versus a single Our Father at 100 MPH?

--
Christopher A. Young
Learn more about Jesus
www.lds.org
..


"rangerssuck"
wrote in message
...

OK, The physics say it's not the same, but did they talk
about closing
speed and reaction time? While you'd have plenty of time to
say "Oh
****!" at 50 mph, you'd barely have time for "Oh sh" at 100.

Just sayin'

"Artemus" wrote in message
...

"Artemus" wrote in message
...

"Existential Angst" wrote in message
...
Awl --

Are two cars hitting each other at 50 mph the same as 1 car hitting an
immovable wall at 100 mph?

Short answer = no.

Longer answer. If the 2 cars are the same mass(weight) they will both
come to a stop at the point of the collision. Now imagine a brick wall
at that point and each car slams into a side. Each car goes from 50mph
to zero in both cases.

Now only use 1 car and the brick wall. That car still goes from 50mph
to 0mph.

In terms of physics each car has energy = 1/2mv^2, where m = mass
and v= velocity. For 1 car going 50mph: 1/2m(50)^2 = 1250m units
The total energy for both cars is 2500m units.
For 1 car going 100mph its energy is 1/2m(100)^2 = 5000m units.
Clearly not the same thing.
Art

I wrote the above before seeing the MB episode.
I have now watched it and am impressed with their experiment with actual
vehicles.

However, they have committed another glaring physics error. Anybody
else catch it too? Hint: it has to do with the clay & pendulum
experiment.
Art

The starting height. They may have used the arc length. PE for a pendulum
depends only on the Y-axis (height).
But I was looking at the heights, it was hard to see if the 2x was really
just the vertical.

"Stormin Mormon" writes:

How do you figure that the kinteic energy is half of MV^2?
"Stormin Mormon" writes:


How do you figure that the kinteic energy is half of MV^2?

Umm.... Freshman physics?
--
As we enjoy great advantages from the inventions of others, we should
be glad of an opportunity to serve others by any invention of ours;
and this we should do freely and generously. (Benjamin Franklin)

On May 6, 8:39*pm, "Stormin Mormon"
wrote:
If I run that through a Street to Catholic translater
computer, would that come out as time for two Hail Marys,
versus a single Our Father at 100 MPH?

--
Christopher A. Young
Learn more about Jesus
*www.lds.org
.

"rangerssuck"
wrote in ...

OK, The physics say it's not the same, but did they talk
about closing
speed and reaction time? While you'd have plenty of time to
say "Oh
****!" at 50 mph, you'd barely have time for "Oh sh" at 100.

Just sayin'

I think you'd need awfully good eyesight to see the wall or the
oncoming truck soon enough to do all that praying. Or, you'd have to
pray really, really fast.

"bw" wrote in message
...

"Artemus" wrote in message
...

"Artemus" wrote in message
...

"Existential Angst" wrote in message
...
Awl --

Are two cars hitting each other at 50 mph the same as 1 car hitting an
immovable wall at 100 mph?

Short answer = no.

Longer answer. If the 2 cars are the same mass(weight) they will both
come to a stop at the point of the collision. Now imagine a brick wall
at that point and each car slams into a side. Each car goes from 50mph
to zero in both cases.

Now only use 1 car and the brick wall. That car still goes from 50mph
to 0mph.

In terms of physics each car has energy = 1/2mv^2, where m = mass
and v= velocity. For 1 car going 50mph: 1/2m(50)^2 = 1250m units
The total energy for both cars is 2500m units.
For 1 car going 100mph its energy is 1/2m(100)^2 = 5000m units.
Clearly not the same thing.
Art

I wrote the above before seeing the MB episode.
I have now watched it and am impressed with their experiment with actual
vehicles.

However, they have committed another glaring physics error. Anybody
else catch it too? Hint: it has to do with the clay & pendulum
experiment.
Art

The starting height. They may have used the arc length. PE for a pendulum
depends only on the Y-axis (height).
But I was looking at the heights, it was hard to see if the 2x was really
just the vertical.


Yup, it's the starting heights. It appeared to me that they used d and 2d for
the heights which does not give v and 2v.
The equation for velocity as a function of distance for a falling object is
v=sqrt(2gd) where g is the acceleration due to gravity.
So to double the velocity they needed to quadruple the starting height.
Instead they got v and 1.414v.
Art

On Thu, 06 May 2010 10:21:00 -0700, Jim Stewart
wrote the following:

Larry Jaques wrote:

Close, but no cigar, since you assumed vehicles of equal mass. If you
have a Chebby Geo meet a Suburban, it will be closer to 75mph Geo vs
25mph Suburban. The doubled mass of the heavier vehicle will keep
pushing until it shoves the Geo a wee bit more. You'd definitely
rather be an occupant in the larger, heavier vehicle.

Only if you are committed to a collision and have
no other options. Otherwise I'd prefer a agile
vehicle with good braking and cornering performance.

And that would be neither a Suburban or a Geo.

I just used those vehicles because Chebby drivers are the ones getting
into accidents all the time. Y'see, their vehicles (other than the
Corvette) are not nimble nor are they quick to stop.

--
All national institutions of churches, whether Jewish, Christian,
or Turkish, appear to me no other than human inventions, set up
to terrify and enslave mankind, and monopolize power and profit.
--Thomas Paine

On Thu, 6 May 2010 14:07:50 -0700, "Artemus" wrote
the following:


"Larry Jaques" wrote in message
.. .
On Wed, 5 May 2010 21:34:52 -0700, "Artemus" wrote
the following:


"Existential Angst" wrote in message
...
Awl --

Are two cars hitting each other at 50 mph the same as 1 car hitting an
immovable wall at 100 mph?

Short answer = no.

Longer answer. If the 2 cars are the same mass(weight) they will both
come to a stop at the point of the collision. Now imagine a brick wall
at that point and each car slams into a side. Each car goes from 50mph
to zero in both cases.

Now only use 1 car and the brick wall. That car still goes from 50mph
to 0mph.

In terms of physics each car has energy = 1/2mv^2, where m = mass
and v= velocity. For 1 car going 50mph: 1/2m(50)^2 = 1250m units
The total energy for both cars is 2500m units.
For 1 car going 100mph its energy is 1/2m(100)^2 = 5000m units.
Clearly not the same thing.
Art

Close, but no cigar, since you assumed vehicles of equal mass. If you
have a Chebby Geo meet a Suburban, it will be closer to 75mph Geo vs
25mph Suburban. The doubled mass of the heavier vehicle will keep
pushing until it shoves the Geo a wee bit more. You'd definitely
rather be an occupant in the larger, heavier vehicle.

I did assume equal mass and stated that. As did the MB. Since you
reject my analysis are you rejecting theirs too?

Of course. "I reject their implied equality of mass." There, I said
it.

--
All national institutions of churches, whether Jewish, Christian,
or Turkish, appear to me no other than human inventions, set up
to terrify and enslave mankind, and monopolize power and profit.
--Thomas Paine

On Thu, 06 May 2010 22:02:07 -0700, Larry Jaques
wrote:

On Thu, 6 May 2010 14:07:50 -0700, "Artemus" wrote
the following:


"Larry Jaques" wrote in message
. ..
On Wed, 5 May 2010 21:34:52 -0700, "Artemus" wrote
the following:


"Existential Angst" wrote in message
...
Awl --

Are two cars hitting each other at 50 mph the same as 1 car hitting an
immovable wall at 100 mph?

Short answer = no.

Longer answer. If the 2 cars are the same mass(weight) they will both
come to a stop at the point of the collision. Now imagine a brick wall
at that point and each car slams into a side. Each car goes from 50mph
to zero in both cases.

Now only use 1 car and the brick wall. That car still goes from 50mph
to 0mph.

In terms of physics each car has energy = 1/2mv^2, where m = mass
and v= velocity. For 1 car going 50mph: 1/2m(50)^2 = 1250m units
The total energy for both cars is 2500m units.
For 1 car going 100mph its energy is 1/2m(100)^2 = 5000m units.
Clearly not the same thing.
Art

Close, but no cigar, since you assumed vehicles of equal mass. If you
have a Chebby Geo meet a Suburban, it will be closer to 75mph Geo vs
25mph Suburban. The doubled mass of the heavier vehicle will keep
pushing until it shoves the Geo a wee bit more. You'd definitely
rather be an occupant in the larger, heavier vehicle.

I did assume equal mass and stated that. As did the MB. Since you
reject my analysis are you rejecting theirs too?

Of course. "I reject their implied equality of mass." There, I said
it.

I'll start this off with a "KNOCK ON WOOD". I've driven Suburbans for
a while. The big damn things will move pretty quickly if you're not
afraid to really yank on them. My worst near miss was on a fishing
trip to Ingleside, Texas (in-laws' place). On an unlit highway, came
across a black horse in the middle of the road at night going 65,
pulling a 20' Bayhawk, I swung into the left ditch, then back up on
the road. I never touched the brakes.

The maneuver damaged nothing except one of the boat trailer bunks fell
over and I had mud on the left side tires and running board. My wife
screamed for the whole two seconds, or was it me? Somebody was. My
youngest son, the Marine, about 8 at the time, got a pretty nasty bump
from banging his head into the left window.

Granted, most housewife type drivers with a phone in their ear would
have collected the horse.

Pete Keillor

anorton wrote:

"Stormin Mormon" wrote in message
...
How do you figure that the kinteic energy is half of MV^2?

--
Christopher A. Young
Learn more about Jesus
www.lds.org
.


You learn it the first couple of weeks in high school physics:
http://en.wikipedia.org/wiki/Kinetic...f_rigid_bodies


Yea. I thought when I read that "Wonder what physics class he took?"
:-)
...lew...

T.Alan Kraus wrote:
It's the media that feeds this falsehood.

Ivan Vegvary

Not just the media but in California the DMV in their driver's license
booklet perpetrates the myth, but what can one expect from a
government agency...

Years ago a friend in Massachusetts failed the drivers license test because of
the True or False question "True or False - Fatique reduces reaction time". The
state license people insisted it was true. The MIT student said it was false.

On May 7, 11:04*am, "Bob F" wrote:
T.Alan Kraus wrote:
It's the media that feeds this falsehood.

Ivan Vegvary

Not just the media but in California the DMV in their driver's license
booklet perpetrates the myth, but what can one expect from a
government agency...

Years ago a friend in Massachusetts failed the drivers license test because of
the True or False question "True or False - Fatique reduces reaction time". The
state license people insisted it was true. The MIT student said it was false.

They may have been defining reaction time as 'time available to react'
or some such.


Dave

On Thu, 6 May 2010 18:05:11 -0400, "Stormin Mormon"
wrote:

How do you figure that the kinteic energy is half of MV^2?

Energy is force * distance. In differential form,

dE = F(x) dx

F = m*A force = mass * acceleration

acceleration A = dV/dt rate of change of velocity

V = dx/dt by definition so dx = V dT

dE = m * dV/dt * V dt = m V dV

integrating,

E = 1/2 * m * V^2

The 1/2 is a constant of integration.

Pete Keillor wrote:

On an unlit highway, came
across a black horse in the middle of the road at night going 65,

How in hell did the horse reach that speed ?


jk

On Fri, 07 May 2010 06:16:02 -0500, Pete Keillor
wrote the following:

On Thu, 06 May 2010 22:02:07 -0700, Larry Jaques
wrote:

Of course. "I reject their implied equality of mass." There, I said
it.

I'll start this off with a "KNOCK ON WOOD". I've driven Suburbans for
a while. The big damn things will move pretty quickly if you're not
afraid to really yank on them. My worst near miss was on a fishing
trip to Ingleside, Texas (in-laws' place). On an unlit highway, came
across a black horse in the middle of the road at night going 65,
pulling a 20' Bayhawk, I swung into the left ditch, then back up on
the road. I never touched the brakes.

Man, you're both smart (not touching the brakes) and lucky (in and out
of a ditch without the usual AOTeakettle Endover Maneuver.)


The maneuver damaged nothing except one of the boat trailer bunks fell
over and I had mud on the left side tires and running board. My wife
screamed for the whole two seconds, or was it me? Somebody was.

I hate it when that happens. bseg


My
youngest son, the Marine, about 8 at the time, got a pretty nasty bump
from banging his head into the left window.

They must make ditches more like swales in Texicus for you to have
driven into and out of it. That wouldn't happen here in OR. They're
24" wide by 18" deep and cut to within a foot of the edge of the
pavement. What goes in, stays in, after stopping rather abruptly.


Granted, most housewife type drivers with a phone in their ear would
have collected the horse.

I've seen the picture of the death to a passenger from a deer when the
hoof came though the windshield. A horse might have squozen through
the opening altogether, or just flattened the entire roof on ya. Maybe
not in a Suburpin'.


--
Live forever or die in the attempt.
-- Joseph Heller, Catch 22

On 2010-05-07, Bob F wrote:
T.Alan Kraus wrote:
It's the media that feeds this falsehood.

Ivan Vegvary

Not just the media but in California the DMV in their driver's license
booklet perpetrates the myth, but what can one expect from a
government agency...

Years ago a friend in Massachusetts failed the drivers license test because of
the True or False question "True or False - Fatique reduces reaction time". The
state license people insisted it was true. The MIT student said it was false.

Now, if it were worded "increased reaction time", I would accept
*that* as true. :-)

Enjoy,
DoN.

--
Email: | Voice (all times): (703) 938-4564
(too) near Washington D.C. | http://www.d-and-d.com/dnichols/DoN.html
--- Black Holes are where God is dividing by zero ---

Bob F wrote:
T.Alan Kraus wrote:
It's the media that feeds this falsehood.

Ivan Vegvary
Not just the media but in California the DMV in their driver's license
booklet perpetrates the myth, but what can one expect from a
government agency...

Years ago a friend in Massachusetts failed the drivers license test because of
the True or False question "True or False - Fatique reduces reaction time". The
state license people insisted it was true. The MIT student said it was false.

In California, you can miss, I think, 3 questions and still pass the
written. The MIT student must have screwed up more than just the one
question.