A completely inelastic collision occurs between two balls of wet putty that move directly toward each other along a vertical axis. Just before the collision, one ball, of mass 5.0 kg, is moving upward at 25 m/s and the other ball, of mass 3.0 kg, is moving downward at 13 m/s. How high do the combined two balls of putty rise above the collision point? (Ignore air resistance.)