A man, attached to an elastic cord, jumps off a platform. He drops $60\,\text{m}$ before he begins to move upward again. The length of the unextended cord is $30\,\text{m}$. The diagrams illustrate four consecutive stages of his descent. At which position are elastic (strain) energy and kinetic energy present?
Physics 0625 · IGCSE · Energy, work and power