A particle rotates on the surface of a sphere. The angular momentum of the particle can be considered as a vector starting at the center of the sphere and pointing outward.

a. In the classical description of the particle, what shape does the tip of angular momentum vector trace out as the particle moves?

b. In the quantum mechanical description of the particle, what shape does the tip of angular momentum vector trace out as the particle moves?

c. Your answer to parts (a) and (b) should be different. What principle makes the quantum mechanical and classical descriptions of the particle correspond?

d. Using the principle in part(c), explain how the quantum mechanical description of the shape the anguar momentum traces out changes into the classical description.