How much energy in kilocalories is expended against gravity alone by a 75- kg man climbing 1500 m up a mountain?

Answer 1

(75 kg) (1500m) (9.8 m/sec2) / 4184 J = 263 kcals

Answer 2

Calculate the gravitational potential energy of the water in a lake of volume 100km^3 (mass=1.0x10^14kg). The lake has an average height of 50m above the hydroelectric generators at the base of the dam holding the water back.