Question

A boy weighing 50 kg climbs up a vertical height of 100m in 200 sec. Calculate the -

(a) amount of work done by him

(b) potential energy gained by him

(c) power of the boy (g = 10m/s²⁾

Answer 1

Here,

Mass of the boy, m = 50 kg

Gravitational force on him = his weight = 50 × 10 = 500 N

a)

He has to apply a force equal to his weight to move upward. So, work done = (500)(100) = 50000 J

b)

The work done by him on himself in going upward is stored in his body as potential energy. So, PE gained by him = 50000 J

c)

We know, Power = work done/time taken = 50000/200 = 250 W