Figure 6
From: Orbit constraint of a small bead on a rotating large circular hoop in a horizontal plane
The variation of work done by the radial and angular components of the constraint force \(N_1\) and friction f with the angle \(\theta\) under different friction coefficients \(\mu\). The work \(W_{N_r}\) and \(W_{N_\varphi }\) done by \(N_r\) and \(N_\varphi\) has a certain periodicity. Radial friction \(f_r\) always does negative work and angular friction \(f_\varphi\) can do positive work.
