Question

Which of the following is an example for a force which does work on a body but fails to change its kinetic energy?

(a) A body pulled through a plain surface

(b) A body pulled through a vertical surface

(c) A body pulled through a horizontal surface

(d) A body at rest

I have been asked this question during a job interview.

This question is from Coefficient of Restitution topic in portion Gravitation of Engineering Physics I

Answer 1

Right option is (c) A body pulled through a horizontal surface

For explanation I would say: When a body is pulled through a rough horizontal surface with constant velocity, work is done by the applied force on the body but the kinetic energy of the body remains unchanged.