In each of the following a force F is acting on an object of mass m. The direction of dispalcement is from west to east shown by the longer arrow. Observer the diagrams carefully and state whether the work done by the force is negative, positive or zero.

Explanation

(i) In case (a), the force F is perpendicular to the displacement. So, the work done is zero.
(ii) In case (b), the force F is in the same direction as that of the displacement. So, the work done is positive.
(iii) In case (c ), the force F is opposite to the direction of displacement. So, the work done is negative.