Is hollow cylinder is stronger than solid cylinder?

Strength to weight ratio is better for a hollow pipe than a solid rod. This means a hollow cylinder is stronger than a rod of equal mass and the same material. A hollow cylinder with a bigger inside diameter is better.

Does a solid or hollow cylinder have more rotational inertia?

The answer is that the solid one will reach the bottom first. In that specific case it is true the solid cylinder has a lower moment of inertia than the hollow one does. (Although they have the same mass, all the hollow cylinder’s mass is concentrated around its outer edge so its moment of inertia is higher.)

Why does a solid cylinder has smaller moment of inertia than a hollow cylinder of same mass and radius when axis of rotation is same?

For a hollow cylinder all the particles are at the same distance from the axis and hence have the same contribution to moment of inertia. On the other hand, for a solid sphere some particles are at different distance from other, thus their contribution to the moment of inertia is less.

Why does a solid disk have a greater moment of inertia than a solid sphere?

Based on the coefficients (2/5 and 1/2), the moment of inertia of solid disk is greater than the moment of inertia of a solid sphere. This phenomenon is caused by the difference in the distribution of mass around the axis.

Why does a cylinder have more inertia than a sphere?

Why is the moment of inertia wrt the center for a hollow sphere higher than a solid sphere with same radius and mass )?

If the spheres are made from the same density material, the solid one will have the higher moment of inertia, because of its larger mass.

Why a hollow shaft is stronger than a solid one of the same mass?

The stiffness of the hollow shaft is more than the solid shaft with the same weight. In the hollow shaft, the material at the centre is removed and spread at large radius. Therefore, hollow shafts are stronger than solid shaft having the same weight.

Why does a disk have a smaller moment of inertia?

The mass distribution is quantified by the Moment of Inertia. A solid disc and a ring will have very different moments of inertia due to the fact that the ring has all of its mass concentrated away from its center while the disc mass sone of its mass closer in.