A 15,000 kg truck and a 2,000 kg car have a head-on collision. Just before impact, the truck is going 25 m/s and the car is going 20 m/s. The coefficient of restitution for the collision is e = 0.2.
a. Find the velocity of the truck just after the collision.
b. If the collision lasts 0.85 seconds, find the average force the truck exerts on the car.