Question

Work done by the centripetal force is always.....................
A. zero
B. infinity
C. more than zero
D. none of these

Answer 1

- Hint – In order to solve this problem you should know that work done by a force is the dot product of force applied on the particle and the displacement of that particle due to that force. Knowing this and centripetal force your problem will be solved.

Complete step-by-step solution -

The centripetal force is always towards the center of the circular path and is responsible to restrict the particle to move in a circle and not responsible for the displacement of the particle.
Any motion in a curved path represents accelerated motion, and requires a force directed towards the centre of curvature of the path.
According to the definition: Work is done whenever the given conditions are satisfied.
(i) a force should act on an object
(ii) there is a displacement of the body caused by the applied force along the direction of the applied force.
No displacement takes place in this case.
So, work done by a centripetal force is always zero.
Hence, the right option is A.

Note – To solve this problem you should know about centripetal force, it's directions and its use as mentioned above. Here we have also used the definition of a work caused by a force. As we found the centripetal force is the force applied due to centripetal acceleration and the force is not responsible for the displacement of the particle. So, the displacement is zero therefore the work done is also zero.