A bungee jumper leaps off a platform and is slowed down by an elastic bungee cord, as illustrated. As he begins the jump, his original gravitational potential energy relative to the ground is transformed into kinetic energy and elastic potential energy in the cord. During which stage of the jump are all three forms of energy non-zero?
- Aon the platform before the jump
- Bon the way down before the cord has started to extend
- Con the way down as he decelerates
- Dat the bottom of the jump when he is stationary