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.
Kinetic energy is given by the expression,
Ek = Kinetic energy of the object moving with a velocity, v
m= Mass of the object
(i) Kinetic energy when the object was moving with a velocity 5 m s−1
Kinetic energy when the object was moving with a velocity 2 m s−1
Work done by force is equal to the change in kinetic energy.
Therefore, work done by force = (Ek)2 - (Ek)5
= 40 − 250 = −210 J
The negative sign indicates that the force is acting in the direction opposite to the motion of the object.
Video Tutorials For All Subjects
- Work and Energy - Kinetic Energy