The mass of a regulation tennis ball is 57 g (although it can vary slightly), and tests have shown that the ball is in contact with the tennis racket for 30 ms. (This number can also vary, depending on the racket and swing.) We shall assume a 30.0-ms contact time for this exercise. The fastest-known served tennis ball was served by “Big Bill” Tilden in 1931, and its speed was measured to be 73.14 m/s.

(a) What impulse and what force did Big Bill exert on the tennis ball in his record serve?

(b) If Big Bill’s opponent returned his serve with a speed of 55 m/s, what force and what impulse did he exert on the ball, assuming only horizontal motion?