A thin, uniform ring of mass m and radius R is attached by a frictionless pin to

Question:

A thin, uniform ring of mass m and radius R is attached by a frictionless pin to a collar at A and rests against a small roller at B. The ring lies in a vertical plane, and the collar can move freely on a horizontal rod and is acted upon by a horizontal force P.
(a) Express the angle θ corresponding to equilibrium in terms of mg, and P.
(b) Determine the value of θ corresponding to equilibrium when 700 m = g and P = 3 N.