Two boys are playing with a ball on a levelled ground. Boy A throws the ball to height of 5 m and boy B throws to height of 7 m from the ground level. The ratio of the work done by A to B is ________.
5: 7
Let mass of ball be m.
Acceleration due to gravity g.
Height attained by the ball thrown by A is 5 m.
Height attained by the ball thrown by B is 7 m.
The ratio of work done by both the boys is the respective change in gravitational potential energies of the ball.
Work done by A = 5mg
Work done by B = 7mg
The ratio of the work done by A to B = 5mg7mg=5 : 7