Question

Certain force acting on a 20 kg mass changes its velocity from 5 m s^–1 to 2 m s^–1 . Calculate the work done by the force.

Answer 1

Mass of the body = 20 kg 

Initial velocity = 5 m/s 

Final velocity = 2 m/s 

We know that ,

Work done = change in kinetic energy

= 1/2 mu² - 1/2 mv²

= 1/2 m (u² - v²)

= 1/2 (20) (5² - 2²)

= 10 (25 - 4)

= 210 J