Question

A body of mass m is moving in a circle of radius r with a constant speed v. The force on the body is $m{v}^2/r$ and is directed towards the centre. What is the work done by the force in moving the body half the circumference of the circle.

• A. $\frac{m{v}^2}{r}\times \pi$ $r$
• B. $\frac{1}{2}m$ $v^2$
• C. $m$ $v^2$
• D. $zero$

Answer 1

The correct option is D $zero$

since the body is in circular motion, the centripetal force $\left(\frac{m{v}^2}{r}\right)$ is directed towards the centre and at any point it is perpendicular to the displacement.

hence the work done is moving the body half the circumstances of the circle is zero.

here (D) is correct answer