I'm having trouble solving this problem. can n e one help me? A bungee jumper of mass 64.5 kg (including safety gear) is standing on a platform 48.0 m above a river. The length of the unstretched bungee cord is 10.1 m. The force constant of the cord is 65.5 N/m. The jumper falls from rest and just touches the water at a speed of zero. The cord acts like an ideal spring. Use conservation of energy to determine the jumper’s speed at a height of 12.5 m above the water on the first fall. I used the work equation to find the total energy, then subtracted the elastic potential energy and gravitational potential energy at 12.5m above ground. Then i solved for Ek, and used THAT equation to solve for speed. i got 9.29m/s, but the answer is 6.37m/s. What did i do wrong?