A jumper weighing 60 kg and tied to an elastic rope, jumps from a bridge that is 40 m high above a river. The length of the rope is 30 m. When jumping, the rope is stretched for 10 m so that the jumper stops just above the river surface.
What is his potential energy before the jump?
What are his potential and kinetic energies when he falls through the length of the rope?
What is the elastic energy of the rope when the jumper is at its lowest point?