Question

a boy of mass 80kg is running at 10m/s find the work done by him

Answer 1

work= force×
distance
so answer is 800 Joules

Answer 2

Mass = 80 kg

Velocity = 10 m/s

kinetic energy = 1/2 m v^2

                        = 1/2 (80)(10)^2

                        = 1/2 (80)(100)

                         =4000 J

Hence the wok done by a boy is 4000 J.

Hope this answer will help u