A stone with a mass of 1.0 kg is tied to the end of a light string which keeps it moving in a circle with a constant speed of 4.0 m/s on a perfectly smooth horizontal tabletop. The radius of the path is 0.60 m. How much work does the tension in the string do on the stone as it makes one-half of a complete circle?
A) 0 J
B) 80 J
C) 40 J
D) 3.8 J
E) 100 J

Question

A stone with a mass of  1.0 kg is tied to the end of a light string which keeps it moving in a circle with a constant speed of  4.0 m/s on a perfectly smooth horizontal tabletop. The radius of the path is  0.60 m. How much work does the tension in the string do on the stone as it makes one-half of a complete circle?
A)  0 J
B)  80 J
C)  40 J
D)  3.8 J
E)  100 J

Quizplus · Accepted Answer

The tension in the string provides the centripetal force necessary to keep the stone moving in a circle but does no work on the stone because the force is always perpendicular to the direction of the stone's velocity.

A Stone with a Mass of 1