The ends of a to two fixed points a, b in the same vertical line, b being depth 2a below a. threaded on the string is a small smooth ring r of mass m. the ring revolves with uniform speed in a horizontal circle with b as centre, the string remain- ing taut. show that br and the uniform speed of the ring light inelastic string, of length 3a, are attached at a 5a/6. find the tension in the string