Adaredevil plans to bungee-jump from a hot-air balloon 65 meters 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 meters 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 meter length of the cord, the daredevil finds his body weight stretches the cord by 1.5 meters. 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 lenght of cord should he use? b) what maximum acceleration will he experience?