(a) A stick of mass m and length 2r is arranged to make a constant angle theta with the horizontal, with its bottom end sliding in a circle on a frictionless ring of radius r. What is the frequency of this motion? It turns out that there is a minimum theta for which this motion is possible; what is it?
(b) If the radius of the ring is now R, what is the largest value of r/R for which this motion is possible for theta -> 0 ?