A 500kg elevator is raised to a height of 10 m in 10 seconds. Calculate the power of the motor.

490 W

49,000 W

4900 W

490,000 W

Correct answer: Third statement P = 4900 W

Explanation:

Given:

m = 500 kg the mass of the elevator

h = 10 m reached height after t = 10 seconds

P = ? power of the motor

The formula for the calculating power of the motor is:

P = W / t

since work is a measure of change in this case of potential energy then it is:

W = ΔEp = Ep - 0 = Ep

In this case we must take g = 9.81 m/s²

Ep = m g h = 500 · 9.81 · 10 = 49,050 W ≈ 49,000 W

Ep ≈ 49,000 W

P = Ep / t = 49,000 / 10 = 4,900 W

P = 4,900 W

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