Question

A force (mv^2/r) is acting on a mass m moving with a velocity v in a circle of radius r. what is the work done by the force in moving the body over half the circumference of a the circle?

Answer 1

Here the work done is zero because the direction of the force is always perpendicular to the direction of motion . Dot product of displacement vector and force vector is always zero

Answer 2

WORK DONE=Force * Displacement

It is so because ,

In circular motion ,displacement is always perpendicular to the direction of force.

So, displacement in the direction of force is zero.

Hence,

WORK DONE= Force * 0

WORK DONE=0.