In one second, of water passes through that particular section. The work done by gravity on this mass of water as it falls through is . This is the amount of energy “wasted” per second; hence the power wasted by the waterfall is .
Not even sure where to start with this one :\
Water flows over a section of Niagara Falls at
a rate of 1.4 x 10^6 kg/s and falls 59 m.
The acceleration of gravity is 9.8 m/s^2.
What is the power wasted by the waterfall?
Answer in units of W.