A tennis ball of mass **m = 0.03 kg** flies towards
a wall with velocity **v = 20 m/s west**.
It hits the wall, stops momentarily,
and then bounces back with the same speed in the
opposite direction.

- What is the ball's initial momentum?
- What is the ball's final momentum?
- What is the
**impulse**, defined as the change in momentumimpulse = (final momentum) - (initial momentum)

- We can simplify things a bit by defining an
**average force**over the course of the impact.If the ball is in contact with the wall for about

**Δt = 0.03 s**, then what is the average force on the ball during that time?

Copyright © Michael Richmond. This work is licensed under a Creative Commons License.