(a) Consider a round object, whose axis when rolling runs through its centre of mass. Mass is m, moment of inertia is I, radius is R. After it has rolled the vertical distance (y), what is its centre-of-mass speed (v)? (b) Consider a uniform hollow cylinder and a uniform solid cylinder rolling down a slope. After a fixed time, the hollow cylinder has descended a distance (y-hollow) and the solid cylinder has descended a distance (y-solid) What is the ratio of these distances?