Sorry if I posted in the wrong section
A uniform heavy rod AB, of mass m and length 4a, can turn in a vertical plane about one end A which is fixed. To the other end B is attached a light elastic string of natural length 3a and modulus (1/2)mg. The other end of the string is attached to a light ring which can slide on a smooth horizontal bar which is fixed at height of 8a above A and in the vertical plane through AB. Find the equilibrium positions of the rod and determine their nature.