Head-on Collision Damage: Comparing 50mph and 100mph Impact Damage

[Brian LB]

If two cars of equal size were each traveling 50mph and hit each other in a head-on collision would the damage sustained best resemble hitting a brick wall at 50mph or 100mph? Assume the full impact of the head-on collision was into each car and not vectoring away from the impact zone.

 

[tiny-tim]

Hi Brian LB! Happy new year!

50 mph … it can't make any difference whether the brick wall is between the two cars or not.

(there was a long discussion on this a few weeks ago at https://www.physicsforums.com/showthread.php?t=456239")

 

[DaveC426913]

If two cars of equal size were each traveling 50mph and hit each other in a head-on collision would the damage sustained best resemble hitting a brick wall at 50mph or 100mph? Assume the full impact of the head-on collision was into each car and not vectoring away from the impact zone.

Each car would appear as if it hit something at 50mph.

Look at a super idealized case: Every 10mph causes the front-end to collapse by 10cm.
At 50mph into a brick wall, the front-end collapses 50cm.
At 100mph into a brick wall, the front-end collapses 100cm.
But at 100mph into another car, the 100cm collapse is shared between them: 50cm per car, just as much as if each car slammed into a brick wall at 50mph.

This is super-idealized because force is a product of velocity squared, so double the speed is quadruple the damage. However, that cancels out in the above scenario.