Cars are designed with crumple zones, so that in a car crash much of the kinetic energy goes into deforming the structure of the car. What if car bumpers acted like large springs instead? In a head-on collision, this might bring the car to rest and then propel the car backwards without causing much damage to the car. If you were an engineer working for one of the big auto manufacturers, would you suggest such a spring-bumper system? Why or why not?
You are driving at high speed along a divided, multi-lane highway when all of sudden you see your evil twin, driving an identical car, going the wrong way and coming directly toward you. You both slam on your brakes, but it's too late to stop and there is about to be a collision. At the last instant you spot a large, very solid immovable object by the side of the road. Which is better for you, to hit your evil twin or to swerve and hit the immovable object instead?
Assume the speed when you collide is the same whether you hit your evil twin or the immovable object, and that your evil twin is going at the same speed you are. Either collision is a head-on collision.
It is better for you to:
The answer is that it doesn't matter. Either collision causes you to come to a complete stop in a distance equal to how far the front of your car collapses, which will be the same in both cases.