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Crumple zone and Impusle, Momentum (1 Viewer)

xiao1985

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Crumble zone is the front bit of the car, which is designed to (well) "crumble" when collision occurs.

You could imagine that if you smash your head against a brick wall, you would experience concussion. But if a pillow would be between you and the wall, the injury you sustain would be less severe.

Crumble zone serve as a disposable pillow in the case when two cars collide. When the cars do collide, the momentem of the cars will be lost. How quickly they lose their momentum is called impulse (rate at which momentum changes).
Obviously, the longer it takes for the car to lose the moment, the smaller the impulse. Crumble zone reduces the impulse by increasing the impact time.

Impulse (or was it called impact? Can't remember) is what causes fatality.
 

Aerath

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Crumple zones increase the time over which the Force is applied. The formula for Impulse is I = Ft. If the impulse is constant, and time is increased, then, force will be reduced.

For example, I = Ft
F = I/t

If time is doubled:
I = F*2t
F = I/2t
Therefore, force is halved.
 

lolokay

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crumple zone increases stopping time, therefore decreasing force and power.
It doesn't have any effect on impulse/momentum, except that the loss of momentum will occur over a longer time. Impulse is constant - it is change in momentum, ie I = mv - mu, and since this does not consider what happens during collision, only it's velocity afterwards (0) there is no effect. Also, I = Ft, and since this is constant force is inversely proportional to time of collision.
 

xiao1985

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lolokay said:
crumple zone increases stopping time, therefore decreasing force and power.
It doesn't have any effect on impulse/momentum, except that the loss of momentum will occur over a longer time. Impulse is constant - it is change in momentum, ie I = mv - mu, and since this does not consider what happens during collision, only it's velocity afterwards (0) there is no effect. Also, I = Ft, and since this is constant force is inversely proportional to time of collision.
What he said. Tis been a while since I last did impulse/momentum stuff.
 

lolokay

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say what? the acceleration is the acceleration from impact>stop, ie final velocity divided by time of impact

also, you might want to add a mass equivalent to the can to the no-can one, if you think this is appropriate for your experiment
 

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