A hydroelectric power facility converts the gravitational potential energy of water behind a dam to electric energy. (For each answer, enter a number.) (a) What is the gravitational potential energy (in J) relative to the generators of a lake of volume 40.0 km?3 (mass = 4.00 x 1013 kag), given that the lake has an average height of 39.0 m above the generators? L s (b) Compare this with the energy stored in a 9-megaton fusion bomb. Bl Boomn =]