A dam produces electricity from the gravitational potential energy of the water stored in it. The same dam has 50 cubic km of water stored 50 meters above the ground. What is the work done by gravity relative to the ground? (Assume g = 10 m/s2)

MCQs on keplers laws, gravitation universal law, gravitational constant, acceleration due to earth gravity, gravitational potential energy, escape speed, earth satellite, orbiting satellite energy, weightlessness, geostationary and polar satellites.