SOLUTION: 5. The energy of a moving body varies directly as the square of its speed. If a body has energy of 5 units at a speed of 3 feet per second, what is its speed when its energy is 20

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Question 1174199: 5. The energy of a moving body varies directly as the square of its speed. If a body has energy of 5 units at a speed of 3 feet per second, what is its speed when its energy is 20 units? (show complete solution using variations thanks!)
Answer by ikleyn(52835) About Me  (Show Source):
You can put this solution on YOUR website!
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The energy increased  4  times;   hence, the speed increased twice.

ANSWER.   The unknown speed is  2*3 = 6  feet per second.