Power: How long will it take a 7.08 hp motor to lift a 250 kg beam directly upward at constant velocity from the ground to a height of 45.0 m? Assume frictional forces are negligible. (1 hp = 746 W)

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Quizplus · Accepted Answer

To find the time, we first convert horsepower to watts: 7.08 hp * 746 W/hp = 5282.88 W. The work done to lift the beam is equal to the gravitational potential energy gained, which is mgh = 250 kg * 9.8 m/s^2 * 45.0 m = 110250 J. The power is the work done per unit time, so time = work / power = 110250 J / 5282.88 W = 20.9 s.

Power: How Long Will It Take a 7