A motor-driven winch pulls a 50.0 kg student 5.00 m up the rope at a constant speed of 1.25 m/s. how much power does the motor use in raising the student? how much work does the motor do on the student?

Question

Dennis Fernandez

Physics

14 June, 10:10

A motor-driven winch pulls a 50.0 kg student 5.00 m up the rope at a constant speed of 1.25 m/s. how much power does the motor use in raising the student? how much work does the motor do on the student?

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Answers (1)

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Roy Lin · Answer 1

Power is the rate work done given by dividing work done by unit time. It is measured in watts equivalent to J/s.

In this case the force by the student is mg = 490 N (taking g as 9.8m/s²)

Work done is given by force * distance,

Therefore, Power = (force * distance) / time, but velocity/speed = distance/time

Thus, Power = force * speed/velocity

= 490 N * 1.25

= 612.5 J/S (Watts)

Hence, power will be 612.5 Watts.