A ball with mass $0.16\ \text{kg}$ is moving horizontally at a speed of $20\ \text{m s}^{-1}$. It strikes a wall and bounces back along the same line with a speed of $15\ \text{m s}^{-1}$. The ball remains in contact with the wall for $1.0\ \text{ms}$. What is the average force exerted by the wall on the ball?
- A$800\ \text{N}$
- B$2400\ \text{N}$
- C$3200\ \text{N}$
- D$5600\ \text{N}$