Question

A body of mass m is moving in a circle of radius r with uniform speed V. The force on the body is $m{V}^2/r$ and is directed towards the centre, what is the work done by this force in moving the body over half the circumference of the circle?

• A. $\left(m{V}^2/r\right)\pi r$
• B. Zero
• C. $m{V}^2/r^2$
• D. $\frac{\pi r^2}{m{V}^2}$

Answer 1

The correct option is B Zero

At every moment the displacement is perpendicular to the force. F.ds =0

dW = $\overline{F}.\overline{d}s=0$

$W=\int \overline{F}.\overline{d}s=0$