Jo decides to try bungy jumping while on an overseas holiday. A rope that could be easily stretched was tied to her ankles and she jumped off a bridge high above a river. Model this as an ideal spring with a spring constant of 20N/m. Jo has a mass of 60kg and, after she jumps, her centre of mass falls vertically a distance of 12m before there is a force exerted on her by the rope.
When the rope reaches maximum extension Jo will be momentarily at rest. What is the upward force that the rope exerts on Jo?
The Attempt at a Solution
When Jo is at rest there is a 600N force downward so the reaction is a tension force of 600N in the rope. This tension is the upward force that the rope exerts on Jo. But the answers suggested the force is 5.4*10^2N. How did they get that?