Question

A 2kg ball is attached to a 0.80m string and whirled in a horizontal circle at a constant speed of 6m/s. The work done on the ball during each revolution is: 

(A) 450 J 

(B) 90 J 

(C) 72 J 

(D) 16 J 

(E) zero

Answer 1

Correct option (E) zero

In a circle moving at a constant speed, the work done is zero since the Force is always perpendicular to the distance moved as you move incrementally around the circle.