Practice Question

1. Explain how seatbelts are designed to protect a car driver during a collision. 

Seatbelts can stretch slightly when the user moves forward during a collision. The vehicle will still experience the same change in momentum, but because of the seat belt stretching, the collision time will occur over a longer time period, so the person experiences a reduced impact force.

2.How does the collision time relate to the impact forces

As collision time increases, impact force decreases.

3. If you are jumping off a wall, why should you bend your knees when you land.

When you jump off the wall, by bending your knees on landing, it will increase the collision time, reducing the impact force you experience.