noticing that R, the radius of the circle on which the penny moves, is just the distance d to the axis of rotation that we were given at the beginning of the problem, and ω, its angul...noticing that R, the radius of the circle on which the penny moves, is just the distance d to the axis of rotation that we were given at the beginning of the problem, and ω, its angular velocity, is just the final angular velocity of the turntable (assuming, as we are told, that the penny has not slipped relative to the turntable).