Work Done by Tension: 2m Rope, 150g Tennis Ball

[cracka97]

Homework Statement

What is the work done per one revolution by tension in a suspended 2m rope with a 150 g tennis ball attached to its end if you swing the rope 2 times a second such that the tennis ball is in a circular trajectory?


2. The attempt at a solution
The work done is the force multiplied the distance. I don't understand how the force of the tension in the rope is traveling a distance which makes me think that the work done is 0.

 

[tiny-tim]

Welcome to PF!

Hi cracka97! Welcome to PF!

The work done is the force multiplied the distance. I don't understand how the force of the tension in the rope is traveling a distance which makes me think that the work done is 0.

That's right! …

work done = integral of force "dot" displacement …

and, for circular motion, the displacement is always perpendicular to to the tension.