A particle moves inside a circular glass tube under the influence of a tangential force of constant magnitude F (Figure 7.54). Explain why we cannot associate a potential energy with this force (which...

A particle moves inside a circular glass tube under the influence of a tangential force of constant magnitude F (Figure 7.54).

Explain why we cannot associate a potential energy with this force (which is therefore a “nonconservative” force). How is

this situation different from the case of a block on the end of a string, which is swung in a circle?