Question

A man lifts a mass of 20 kg to a height of 2.5 m. Assuming that the force of gravity on 1 kg mass is 10 N, find the work done by the man.

Answer 1

Mass = 20 kg h = 2.5 m

Force of gravity on a mass of 1 kg = 10 N

Force of gravityona mass of 20kg

F = mg = 20 × 10 = 200 N

Work done in lifting the mass to height h = 20 m is

W = F × h

= 200 N × 2.5 m

= 200 × 25/10 =500 J