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A bread gives a boy of mass 40 kg an ene...

A bread gives a boy of mass 40 kg an energy of 21 kJ. If the efficiency is 28%, then the height that can be climbed by him using this energy, is :

A

22.5 m

B

15 m

C

10 m

D

5 m

Text Solution

Verified by Experts

The correct Answer is:
B
Energy `=21 xx1000 xx 28/100 = 5880 J`
Energy = mgh
`implies 5880 = 40 xx10 xx h`
`h = (588)/40 = 14.7 m ~~ 15 m`
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