Question

A 0. 5 kg mass on a 1-m-long string swings in a circle on a horizontal, frictionless table at a steady speed of 2 m/s. How much work does the tension in the string do on the mass during one revolution?

Answer 1

The tension does no (zero) work

F· S = W

Since the tension is perpendicular to the direction of motion, and there is no change in S the work done is zero.