Chapter 6, Problem 1QAP

To determine

The condition when the work done on an object by a force can be equal to zero.

Explanation of Solution

Introduction:

When a force is applied on a body and it is moved at some distance in the direction of force, then work is said to be done.

The mathematical relation of work done is,

  $W=F\times d\times \cos \theta$

Where,

F is the applied force.

d is the total distance travelled by an object.

  $\theta$ is the angle between the force and displacement.

So, the work done will be zero when either force or displacement is zero. Also, it can be zero if force and displacement are perpendicular to each other even if they are non-zero quantities.

Conclusion:

Thus, the amount of work done will be zero if displacement is zero and, when force is perpendicular to the displacement.