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## Main Question or Discussion Point

**Situation 1: completely horizontal circle**

Imagine a ball being whirled in a completely horizontal circle.

The only forces acting are tension and weight

Would I be correct in assuming that in this situation NO WORK is done on the ball because the forces are directed (at all times) perpendicular to the direction of motion (there is never a resultant force along the line of motion)

**Situation 2: completely vertical circle**

Imagine a ball being whirled in a completely vertical circle.

The only forces acting are tension and weight

at all points (except for the top and bottom of the circle) components of the force act along the same line as the direction of motion, right?

Therefore, would I be correct in assuming that in this situation, work is ALWAYS done on the ball (except at the top and bottom)

**Are both my assumptions (for situation 1 and 2) correct?**