(a) Calculate the change in potential energy of 1 kg of water as it passes over Niagara Falls (a vertical descent of 50 m).
(b) At what rate is gravitational potential energy lost by the water of the Niagara River? The rate of flow is 5.5 × 106 kg/s.
(c) If 10% of this energy can be converted into electric energy, how many households would the electricity supply? (An average household uses an average electrical power of about 1 kW.)