試題詳解

39. On a bridge, a man (weight = 70 kg) plays bungee jumping by tying himself to one end of an elastic rope. The rope has a length of 100 m, and the height of the bridge is 500 m. After jumping, the man begins to bounce back 10 seconds later. What is the effective weight of the man at the bouncing point? (Gravitational acceleration g = 10 m/s2 )
(A) 83 kg
(B) 95 kg
(C) 102 kg
(D) 117 kg
(E) 127 kg