A hard-thrown tennis ball is moving horizontally when it bangs into a vertical concrete wall at perpendicular incidence. The ball rebounds straight back off the wall. Neglect any effects due to gravity for the small time interval described here. Assume that toward the wall is the +x direction.
(a) What are the directions of its velocity and acceleration just before hitting the wall?
(b) What are the directions of its velocity and acceleration at maximum impact?
(c) What are the directions of its velocity and acceleration just after leaving the wall?