1. The problem statement, all variables and given/known data "A Daredevil plans to bungee-jump from a hot-air balloon 65.0 m above a carnival midway. He will use a uniform elastic cord, tied to a harness around his body, to stop his fall at a point 10.0 m above the ground. Model his body as a particle and the cord as having negligible mass and obeying Hooke's law. In a preliminary test, hanging at rest from a 5.00-m length of the cord, the daredevil finds his body weight stretches the cord by 1.50 m. He intends to drop from rest at the point where the top end of a longer section of the cord is attached to the stationary hot-air balloon. (a) What length of cord should he use? (b) What maximum acceleration will he experience? 2. Relevant equations Hooke's Law: [tex]F=-kx[/tex] Most likely other equations. 3. The attempt at a solution For part (a) I know I will be using Hooke's law, but my problem is I was not given the mass of the "daredevil". I know I need to use the fact that the daredevil's weight stretched a 5.0m section of the cord by 1.5m, but I do not know what the correlation is without being given the mass. I have not yet attempted part (b), but I am guessing that he will experience the maximum acceleration when the cord is fully stretched and is just about to reverse his downward direction. If that is true, then I would probably use Hooke's law again, substituting the distance the cord will stretch for x. I know the rules state that you guys are not supposed to give me the answer, but I just want to reiterate, I only want help with this, if I cannot yet solve a problem like this on my own then I need to realize that now and not during an exam. Thank you very much in advance!