Question

A boy having a mass of 50 kg runs up the mountain. the total work done by a boy is 700J. Calculate the force exerted by him to complete the work.​

Answer 1

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Given,

mass of boy = m = 50 kg

height = h = 100m

since boy does not move anything with his force, work done by him is zero

work done on the boy = gain in potential energy

P.E=mgh

P.E=50×9.8×100

P.E=49KJ

so, potential energy gained by boy is 49 KJ

Answer 2

Answer:

490 Newton

Explanation:

The force = Mass * Acceleration....

The force = Mass * Gravitational Acceleration (As the boy is moving upward against the gravitational force)

Therefore the force exerted on him by gravity should be

50*9.8 = 490 Newton

According to the Newton's 3rd Law of Motion force exerted by him on earth should be 490 Newton too