posted by sam .
A tennis ball with a speed of 14m/s is moving perpendicular to a wall. After striking the wall, the ball rebounds in the opposite direction with a speed of 11.41m/s. If the ball is in contact with the wall for 0.0112s, what is the average acceleration of the ball while it is in contact with the wall? Take "toward the wall" to be the positive direction.
Answer in unite of m/s^2