Does Tension Do Any Work in Uniform Circular Motion?

AI Thread Summary
In uniform circular motion, the tension in the string does no work on the ball because it acts perpendicular to the direction of displacement at all points in the circle. Therefore, the total work done by tension during one complete circle is zero. In contrast, gravity does work on the ball as it moves along its path, which can be calculated based on the change in height. For semicircular motion, the work done by gravity can be determined by the vertical displacement from the lowest to the highest point. Understanding the relationship between force direction and displacement is crucial for solving these types of physics problems.
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Homework Statement



A ball of mass 0.765 kg is tied to the end of a string of length 1.59 m and swung in a vertical circle.

During one complete circle, starting anywhere, calculate the total work done on the ball by the tension in the string.

During one complete circle, starting anywhere, calculate the total work done on the ball by gravity.

Repeat part (a) for motion along the semicircle from the lowest to the highest point on the path.

Repeat part (b) for motion along the semicircle from the lowest to the highest point on the path.

Take all free fall acceleration to be 9.8 m/s^s


Homework Equations




W = F * s
K = .5mv^2


The Attempt at a Solution



For the first part,

I tried getting the C, by using C = 2pi1.59^2
c = 9.99
then 9.8(9.9) = 97.02, but it's incorrect :(
 
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