A porter lifts a luggage of 15 kg from the ground and puts it on his head 1.5 m above the ground. Calculate the work done by him on the luggage.

Solution:
Mass of luggage, m = 15 kg and
displacement, s = 1.5 m.

Work done, W = F × s = mg × s
= 15 kg × 10 m s^-2 × 1.5 m
= 225 kg m s^-2 m
= 225 N m = 225 J
Work done is 225 J.