CHAPTER 5:

25. What is the potential energy of the water in a lake of surface area 10 square miles, average depth 40ft, and elevation above the electrical generator of 400ft? (Note that 1 square mile is about 28 million square feet and that 1ft3 of water weighs 62lb.) Calculate the answer in foot-pounds, not Joules: it’s much easier. 27. ................
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