Imagine a bungee jumper dropping from a high cliff. When he reaches the point where the rope is just about to be stretched we can say he has reached his max. velocity. Then the rope will be stretched and when it has reached its maximum deformation, the jumper will "bounce" up and again make the rope stretch, this time a smaller distance. My question is: if I want to calculate the constant, k, of the rope, I think I should use the Hooke's equation, where F=kx, where F is going to be the jumper's mass times g, and x is the maximum deformation of the rope. However...when the jumper stretches the rope for a second time, "x" is going to be smaller, but of course the jumper's weight is the same. So it is obvious that something extra needs to be put into the equation to account for the speed the jumper had when he first dropped and stretched the rope. How do you correctly calculate k?? Thanks in advance.