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Question
A man weighing 700 N runs up a flight of 15 steps, each 20 cm high, in 5 seconds. Calculate the power of the man.
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Solution
Total height covered = 15 × 20 cm
= 300 cm
= 3 m
Work done = Force × distance
= 700 N × 3 m
= 2100 J
Since the time taken is 5s, the power of the man is
Power = (2100/5) Js−1
= 420 W.
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