A body of mass m is moving in a circle of radius r with a constant speed v, The force on the body is `(mv^(2))/(r )` and is directed towards the centre what is the work done by the from in moving the body over half the circumference of the circle?

Options

A. `(mv^(2))/(pir^(2))`
B. Zero
C. `(mv^(2))/(r^(2))`
D. `(pir^(2))/(mv^(2))`

Answer

B

Explanation

Work done by centripetal force is always zero, because force and instantaneous displacement are always perpendicular.
`W = vec(F).vec(s)=Fs cos theta = Fs cos (90^(@))=0`