A 65 kg bungee jumper jumps off of a bridge. At an instant when they are 50 m above the ground, they are falling at a speed of 40 m/s, and the elastic in their bungee cord
(k = 650 N / m) is stretched by a distance of 2.0 m. What is the total mechanical energy of the bungee jumper at this instant ?
a. 1300 J
b. 52000 J
c. 31850 J
d. 85150 J