23. You drop two balls of equal mass, made of rubber and putty, from the same height h above a horizontal surface. The rubber ball bounces up after it strikes the surface while the putty ball comes to rest after striking it. Assume that in both cases the velocity of the ball takes the same time At to change from its initial to its final value due to contact with the surface. Compare the average forces Fr and FP exerted on the surface by the rubber and putty balls, respectively, during time At. a. Fr Fp e. Fr may be smaller or larger than Fp depending upon the relative size of the balls.