A person jumps from a balloon 65m above the ground. He will stop 10m above the ground. A 5m length of the same cord stretches 1.5m with his body weight. He will drop from rest at the point where the top end of a longer section of the cord is attached to the stationary balloon. What length of cord should the jumper use? Is the spring or elastic constant (mg/1.5)? If it is how do I set up the equation? I know that mgyi=65m, and mgyf=10m.