2. Two 145-lb adventure seekers, A and B, intend to bungee-jump off a 115-ft high bridge using an elastic cord with a stiffness k = 75 lb/ft. They want to come to rest just as they reach the surface of the river, at which point A, who is attached to the cord, releases B, who is not attached to the cord. a. What is the necessary unstretched length, l0, of the cord? b. What is the maximum acceleration of A? c. What is the maximum height A reaches after the rebound? d. What are the chances that A lives to tell about his experience?