Happy new year everyone, if I were to bungee jump off a building height H using a cord with an elasticity of 150 N/m 15 m long when it isn't stretched that is tied to a rope of length L (does not stretch), and I have a mass of M and the cord stretches X meters. Gravity is pulling at 10 m/s^2. I want to go as close to the ground as possible when I step off the building. What should the length of rope be? I know that at the bottom, mgh=1/2kx^2. I also know that the cord + rope is slightly less than the height of the building (L + X = H). The force on the cord must also decrease as the length of rope gets smaller because there is less time for gravity to accelerate me. I also tried Velocity = 2aΔy. Once again, mass = M building height = H Cord length = 15m Cord elasticity = K = 150N/m Rope length = L Gravity = 10 m/s^2 We need to know the rope length L. Am I missing something or doing something wrong? Any and all help is much appreciated!