A man lifts, vertically, a weight of 40 kg through Im in 10s: while a child lifts, vertically, a weight of 10 kg through a distance of Im in Is. What will be correct inference? (g = 10 m/s2)
Correct answer: C. Child has more power than man
- A. Man has more power than child
- B. Both have same power
- C. Child has more power than man
- D. It is a foolish question
Explanation
Wman = mgh = (40)(10)(1) = 400 JP = Wman / t = 400 / 10 = 40 wattWchild = mgh = (10)(10)(1) = 100 JP = Wchild / t = 100 / 1 = 100 watt
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Power is the rate at which work is done or energy is transferred, with average power calculated over a time interval and instantaneous power found from P = Fv when force and velocity are aligned. Work includes units, mechanical efficiency, and the distinction between power and total work or energy.
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