A body of mass m is moving in a circle of radius r with a constant speed v. The

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 centre. What is the work done by this force in moving the body over half the circumference of the circle

Options:

A . mv2πr2

B . Zero

C . mv2r2

D . πr2mv2

Answer: Option B
:
B
Work done by centripetal force is always zero, because force and instantaneous displacement are always perpendicular.

W = \to F . \to s = F s c o s θ = F s c o s 90^{\circ} = 0

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