Question

What work is done by a body moving along a circular path? Explain.

Answer 1

Mathematically, work done is given by

$W=Fscos\theta$

Where F is a force, s is a displacement and $\theta$ is an angle between force and displacement,

We know that force in a uniform circular motion is perpendicular to the displacement.

Thus, the angle between F and s is ${90}^{\circ }$

Putting $\mathit{\theta }\mathbf{=}{\mathbf{90}}^{\mathbf{\circ }}$in the equation of work done,

$\mathit{W}\mathbf{}\mathbf{=}\mathit{F}\mathit{s}\mathit{c}\mathit{o}\mathit{s}{\mathbf{90}}^{\mathbf{\circ }}$

$\mathbf{=}\mathbf{0}$ $\mathbf{(}\mathit{c}\mathit{o}\mathit{s}{\mathbf{90}}^{\mathbf{\circ }}\mathbf{=}\mathbf{0}\mathbf{)}$

Hence, work done by a body moving along a circular path is zero.