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

Work is said to be done when a force applied to an object moves that object. Work done is generally referred to in relation to the force applied while energy is used in reference to other factors such as heat.

Kinetic energy is given by the expression,

(K. E)v = 1/2 mv2

Where,

1. E = Kinetic energy of the object

v = velocity of the object

•  Kinetic energy when the object was moving with a velocity of 5 m/s

(K. E)5 = 1/2 × 20 × (5)2

(K. E)5 = 250 J

• Kinetic energy when the object was moving with a velocity 2 m/s

(K. E)2 = 1 /2 × 20 × (2)2

(K. E)2 = 40 J

Work done = Change in kinetic energy

= 40 J – 250 J

= – 210 J

Therefore, work done = -210 J

Check out the video given below to know more about kinetic and potential energy.