A very naive, but partially correct, way to understand quantization of angular momentum is as follows. Imagine that a particle is confined to travel around a circle of radius r. Its angular momentum about the center is then ±rp, where p is the magnitude of its linear momentum at any moment. Let s be a coordinate that labels the position of the particle around the circle, so that s ranges from 0 to 2πr. The wavefunction of this particle is a function of s. Now suppose that the wavefunction is sinusoidal, so that p is well defined. Using the fact that the wavefunction must undergo an integer number of complete oscillations over the entire circle, find the allowed values of p and the allowed values of the angular momentum.