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 $\frac{m{v}^2}{r}$ and is directed towards the center. The work done by the force in moving body over half the circumference of the circle is:

• A. $\frac{m{v}^2}{r}\times \pi r$
• B. $0$
• C. $\frac{m{v}^2}{r}$
• D. $\frac{\pi r^2}{m{v}^2}$

Answer 1

Answer: (B)

$0$

Centripetal force is perpendicular to the motion of body.

So, $W=\overrightarrow{F}.\overrightarrow{d}=Fd\cos {90}^0=0$