### Conservation of Momentum and Collision Review

1. A car crashes into a wall at 25 m/s and is brought to the rest in 0.1 s. Calculate the average force exerted on a 75-kg test dummy by the seat belt. 2. A railroad diesel engine weighs four times as much as a freight-car. If the diesel engine coasts at 5 km/h into a freight-car that is initially at rest, how fast do the