6-14. A horizontal turntable rotates at a constant rate @ about a fixed vertical axis through its center O. A particle of mass m can slide in a frictionless circular groove of radius r centered at O' which is r/3 from O. The particle is disturbed slightly from 'the initial conditions 8(0) = 0, (0) = 0 in the direction of positive 8, where 0 is measured relative to the turntable. Find: (a) the differential equation for 8; (b) @ as a function of @; (c) the maximum constraint force acting on the particle.