Question

A hollow sphere is held suspended. Sand is now poured into it in stages. The centre of gravity of the sphere with the sand
(a) rises continuously
(b) remains unchanged in the process
(c) First rises and then falls to the original position
(d) First falls and then rises to the original position

Answer 1

D is the correct option

Answer 2

Answer:

(D) First falls and then rises to the original position

Explanation:

When no sand will be poured, the center of gravity will be at the center of the hollow sphere.  Thus, when we start to pour sand, it will start filling from the bottom. Therefore during the initial state, since the mass is more concentrated at the bottom, the center of gravity will start moving downwards from the initial position

Whereas once the sphere is half filled, then the mass gets accumulated on the top half of the sphere as well and hence the center of gravity rises. The center of gravity will again reach at the center, once the sphere is fully filled with sand.