The following three questions refer to a situation in which a driver is in a car that crashes into a solid wall. The car comes to a complete stop without bouncing back. The car has a mass of 1500 kg and has a speed of 30 m/s before the crash (this is about 65 mph). The driver has a mass of 60 kg. 1) What is the car's initial momentum? What is the person's initial momentum? What is the change in the momentum of the car? What is the change in the person's momentum?
2) What is the net impulse that acts on the car to bring it to a stop? What is the net impulse that acts on the person to bring them to a stop? Do these numbers depend on the details of the crash? Why or why not?
3) What object delivers the impulse that brings the car to a stop? What object delivers the impulse that brings the person to a stop? Think about what happens during such a crash, and discuss the role each of the factors below plays in the ultimate fate of the driver. Be sure to include what objects exert forces on what other objects, and use the model of impulse & momentum to estimate the strength of these forces.
a) "crumple zone" of the front of the car.
b) use or non-use of seat belt.
c) deployment or non-deployment of airbag.