Problem 1.159:.A body of mass $‘m’$ is moving in a circle of radius with a constant speed $‘v’$. Calculate the work done by the resultant force in moving the body over half circumference and full circumference respectively.

Solution:

This is motion along a circular path. Resultant force on the particle produces the necessary centripetal force.

problem-1-159

Centripetal force is directed toward the center of the path and velocity is tangential to the path.

Therefore  resultant force is always perpendicular to the velocity.

This makes work done zero as there is no change in speed and kinetic energy of the body.

Then the work done by the resultant force in moving the body over half circumference and full circumference respectively are zero.