Halliday, Resnick & Walker — Potential Energy and Conservation of Energy: Problem 61

61 A 10.0 kg block falls 30.0 m onto a vertical spring whose lower end is fixed to a platform. When the spring reaches its maximum compression of 0.200 m, it is locked in place. The block is then removed and the spring apparatus is transported to the Moon, where the gravitational acceleration is g/6. A 50.0 kg astronaut then sits on top of the spring and the spring is unlocked so that it propels the astronaut upward. How high above that initial point does the astronaut rise?