Question

a boy standing on building slowly pulls an object of mass 10 kg from the ground till the height 5 m in 2 seconds the total power expended by him

Answer 1

Given, mass=10kg. , height =5metre,time=2sec. We know power=work done/time. And work done=force multiplied by displacement (s)

W=fs and force,f=mass multiplied by acceleration
f=MA=100N
W=100.5=500J
Power,p=w/t
So, p=500/2=250w

Answer 2

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