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Which factors determine the energy required to raise a flag from the ground to the top of a tall flagpole using a pulley? Does raising the flag slowly or quickly change the amount of work done? If the speed at which the flag is raised is doubled, how does the power requirement change? Explain your answers.
Show Answer
The energy (work) needed depends on the weight of the flag and the height of the pole : \(W = mgh\).
Raising it slowly or quickly does not change the work done (work depends on force and distance, not time).
If the speed is doubled, the time halves, so power \(P = \dfrac{W}{t}\) doubles .
