Approximately 5.5 x 100 kg of water falls 50 m over Niagara Falls each second. a) What is the decrease in the gravitational potential energy of the water-Earth system each second? b) If all this energy could be converted to electrical energy (it cannot be), at what rate would electrical energy be supplied? (The mass of 1 m of water is 1000 kg.) c) If the electrical energy were sold at 1 cent/kWh, what would be the yearly income?