A 20kg child lifts his 0.5kg ball of the floor to put it away on his bookshelf 1.5 meters above the ground. How much work has he done?

Work done by the boy is 7.50 J

Explanation:

mass of the ball m = 0.5kg

height of the bookshelf h = 1.5 m

acceleration due to gravity = 10 m/s²

work done = ?

Workdone = force * distance

In this case Weight = Force

Workdone = mgh

= 0.5 * 10 * 1.5

= 7.50 J