Answer:
Explanation:The rotational inertia of any object depends directly on the distance the mass is from the axis of a rotating object
Having more mass at the sides will increase the rotational inertia of the object that is why a Hollow sphere having same M and R as the solid one has more rotational inertia as it has more mass at the sides.
The sphere have some mass at the center but most of its mass is closer to its radius and thus have more inertia than flat Disk.
The same relation exist between a flat disk and hollow sphere. The hollow sphere have some mass at the center but most of its mass is closer to its radius and thus have more inertia.
The rotational of the objects can be calculated by these equations