Assignment:
"A tennis ball with a speed of 11.8 m/s is thrown perpendicularly at a wall. After striking the wall, the ball rebounds in the opposite direction with a speed of 8.51 m/s. If the ball is in contact with the wall for 0.00175 s, what is the average acceleration of the ball while it is in contact with the wall? Define the initial direction of the ball's motion to be positive."