Question

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

Answer 1

(i)

Since in this diagram displacement is perpendicular to the direction of force, so work done is zero.
(ii)

Since in this diagram displacement is in the direction of force, so work done is positive.
(iii)

Since in this diagram displacement is in the opposite direction of the force applied hence work done is negative.