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  #16  
Old 07-01-2010, 12:25 PM
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He must've been looking at the nose of the caravan when he said 60, ...

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  #17  
Old 07-01-2010, 12:27 PM
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yeah. I'd love to see the pics of the caravan...
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  #18  
Old 07-01-2010, 01:13 PM
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Quote:
Originally Posted by vstech View Post
Really? seriously? Mythbusters disproved it? Do I have enough ?marks? I cannot believe a 60mph crash into a wall is equal energy as a 60mph crash into a car doing 60mph... mind blowing...
It seems to me that the mass of the two vehicles has a lot to do with it. If you have two 300SD's in a head on, each will absorb equal energy, as they are the same mass. So I can go with the analysis that it would be equal to one SD hitting a wall. (May this never happen to any of our cherished Benzes.)

Now, to use an extreme example to make a point, suppose you have a Smart Car in a head on at 60 mph with with a cement truck. The Smart Car will end up going in the opposite direction, that is, backwards, at the instant after impact. So it will be a greater force to the Smart Car than hitting a wall at 60.

The cement truck driver, if he was on his cell phone or sneezing at the time of impact, I suppose may only think he hit a deer or raccoon.
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  #19  
Old 07-01-2010, 01:21 PM
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When you hit a wall at 50 mph it pushes back with the same energy as another car exactly like yours moving at 50 mph, otherwise the wall would move.

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  #20  
Old 07-01-2010, 01:30 PM
Craig
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RML is correct, the kinetic energy of each vehicle is (m*v^2)/2. After the collision, all that energy will be conserved, either as the continued motion of one or both vehicles or as damage (absorbed energy) to one or both vehicles. If the vehicles are of different masses and/or traveling at different speeds, one may absorb more or less energy than it contributes.
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  #21  
Old 07-01-2010, 01:31 PM
Craig
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Originally Posted by compu_85 View Post
When you hit a wall at 50 mph it pushes back with the same energy as another car exactly like yours moving at 50 mph, otherwise the wall would move.

-J
Yes.
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  #22  
Old 07-01-2010, 01:32 PM
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Originally Posted by thayer View Post
If I am going 60, and you are going 60, and we crash into each other head on...wouldn't you need to add our velocities? It would make sense that your force and my force both must be dispersed.

Just thinking out loud
Don't confuse the guy with facts.
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  #23  
Old 07-01-2010, 01:43 PM
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Originally Posted by vstech View Post
and pics of the other guy?
no WAY that was a 100kph impact!!! (it does look like your control arm would have failed soon anyway, that's a lot of rust in there!) I've seen worse damage done from a 30mph impact... that'd be what 50-60kph...
Precisely.

The only way the car "doing 60 mph" did that little of damage, was if the beer/cigar car was doing 60+ mph.

Max. impact looks more like 30 mph OR LESS.

The beer and cigars seemed to have gotten lost in this story.
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  #24  
Old 07-01-2010, 02:36 PM
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Quote:
Originally Posted by compu_85 View Post
When you hit a wall at 50 mph it pushes back with the same energy as another car exactly like yours moving at 50 mph, otherwise the wall would move.

-J
I remember a science teacher when I was in the 8th grade (1958) telling us this same thing. when you push on a wall, the wall pushes back with the same amount of resistance, until it is over come with the greater force. (or something like that, loooooong time ago).


SOOOOOOOOOO, do we have any takers here to do some high speed tests?
Head on with 2 W123, or W126. Head on into a wall, etc.......... then see what the out come will be.
Also all depends on the amount of structural rust, if one is rusty and the other isn`t to the amount of damage.

How about a head on with a Smart car and a 126? either way here, the Smart car might survive, the driver wont. the W126 will fare better.


Any way, it sucks you got hit, at least you were not hurt, and the Cigars and beer didn`t get damaged.
Once you get in there checking the damage, hope it isn`t as bad as it looks and get her back on the road.

Charlie
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  #25  
Old 07-01-2010, 02:43 PM
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Originally Posted by charmalu View Post
How about a head on with a Smart car and a 126? either way here, the Smart car might survive, the driver wont. the W126 will fare better.
Not a W126, but close enough.
http://www.youtube.com/watch?v=02eghIfyHP0
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  #26  
Old 07-01-2010, 03:39 PM
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sooo does that prove anything?
mass/inertia is transferred into the smart... unequal masses. would it bounce and flip if it hit a wall?
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  #27  
Old 07-01-2010, 05:35 PM
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Quote:
Originally Posted by charmalu View Post
I remember a science teacher when I was in the 8th grade (1958) telling us this same thing. when you push on a wall, the wall pushes back with the same amount of resistance, until it is over come with the greater force. (or something like that, loooooong time ago).


SOOOOOOOOOO, do we have any takers here to do some high speed tests?
Head on with 2 W123, or W126. Head on into a wall, etc.......... then see what the out come will be.
Also all depends on the amount of structural rust, if one is rusty and the other isn`t to the amount of damage.

How about a head on with a Smart car and a 126? either way here, the Smart car might survive, the driver wont. the W126 will fare better.


Any way, it sucks you got hit, at least you were not hurt, and the Cigars and beer didn`t get damaged.
Once you get in there checking the damage, hope it isn`t as bad as it looks and get her back on the road.

Charlie
the cigars survived the beer not so much out only 9 out of 24 , like I said the cop said 90-100. All I care about is that we all walked away without injury. It sucks for the other guy he didn't have his seat belt on, no insurance, expired sticker, speeding and his van is totaled unfortunately the cop wouldn't let me take pictures of the other guys car.
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  #28  
Old 07-01-2010, 05:51 PM
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Originally Posted by 635CSi View Post
the cigars survived the beer not so much out only 9 out of 24 , like I said the cop said 90-100. All I care about is that we all walked away without injury. It sucks for the other guy he didn't have his seat belt on, no insurance, expired sticker, speeding and his van is totaled unfortunately the cop wouldn't let me take pictures of the other guys car.
Whaaat!!!! cop would not let you properly document the accident? methinks any lawyer worth his salt would seriously attack that mentality!!!
cop should protect you from taking pics of the driver, but not of the accident damage, including the damage to the other vehicle.
how are you going to show serious mental anguish and personal injury with only the damage from your superb vehicle as examples?
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John HAUL AWAY, OR CRUSHED CARS!!! HELP ME keep the cars out of the crusher! A/C Thread
"as I ride with my a/c on... I have fond memories of sweaty oily saturdays and spewing R12 into the air. THANKS for all you do!

My drivers:
1987 190D 2.5Turbo
1987 190D 2.5Turbo
1987 190D 2.5-5SPEED!!!

1987 300TD
1987 300TD
1994GMC 2500 6.5Turbo truck... I had to put the ladder somewhere!
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  #29  
Old 07-01-2010, 07:01 PM
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Find out where his vehicle was taken and go there and get pics.
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  #30  
Old 07-01-2010, 07:15 PM
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You can address collisions with the conservation of momentum. The momentum of a system does not change through the process of a collision. From this you can also say that the velocity of the center of mass of the system does not change through the collision process. (ideally speaking. In reality, you have braking, skidding, etc. that affect the velocity & momentum.

Consider 2 cars, moving in opposite directions.

Equal mass:
Momentum of A = Ma * Va = 2000 kg * 50 m/sec = 100000 kg *m/sec
Momentum of B = Mb * Vb = 2000 kg * -50m/sec (opposite direction, equal speed) = -100000 kg * m/sec

The momentum of the system = (100000 -100000 ) kg * m/sec = 0

Unequal mass, equal & opposite speed:
Momentum of A = Ma * Va = 2000 kg * 50 m/sec = 10000 kg * m/sec
Momentum of B = Mb * Vb = 1000 kg * -50 m/sec = -50000 kg * m/sec

Total momentum, before & after collision of the system:
(100000-50000) m/sec = 50000 kg *m/sec

Velocity of the system = momentum / mass

velocity = 50000 (kg m*/sec)/3000 kg = 16.7 m/sec

Velocity change for the heavy car = (50 - 16.7) m/sec = 33 m/sec
Velocity change for the light car = (-50-16.7) m/sec) = 66.7 m/sec

So in this case it hurts to be in the small car.

This neglects so many aspects of a collision, but fundamentally conservation of momentum applies.

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