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