Question

(b) A stone of mass 1kg is whirled in vertical plane in a circular path of radius 1m with
a speed of Im/s. The work done by the centripetal force is​

Answer 1

Given:

A stone of mass 1kg is whirled in vertical plane in a circular path of radius 1m with a speed of I m/s.

To find:

Work done by centripetal force?

Calculation:

The work done can be calculated as :

$\rm \: W = \vec{F}. \vec{s}$

$\rm \implies \: W = F \times s \times \cos( \theta)$

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

• In circular motion, value of $\theta$ = 90°.

$\rm \implies \: W = \dfrac{m {v}^{2} }{r} \times s \times \cos( {90}^{ \circ} )$

$\rm \implies \: W = \dfrac{m {v}^{2} s}{r} \times 0$

$\rm \implies \: W = 0 \: joule$

So , work done by centripetal force is zero joule.