Water flows over a section of Niagara Falls at a rate of 2.3e6 kg/s and falls 70 m.?

Question

Water flows over a section of Niagara Falls at a rate of 2.3e6 kg/s and falls 70 m. The acceleration of gravity is 9.8 m/s^2. What is the power wasted by the waterfall? Answer in units of W.

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Given: 1 hp = 746 W and 1 m/s = 2:237 mi/h. When an automobile moves with constant velocity, the power developed in a certain engine is 114 hp.
What total frictional force acts on the car at v = 74.9 mi/h? Answer in units of N.

Answer 1

The power = g*2.3e6*70 = 1.5778 gw. How much is "wasted" is partly a value judgment and partly depends on whether the power plant there (ref.) uses that part of the falls, and how much of its current capacity is in use.