Question

A hollow sphere is held suspended, sand is now poured in it.The centre of gravity of the sphere with the sand :

• A. Rises continuously
• B. Remains unchanged
• C. First rises and then falls to original position
• D. First falls and then rises to original position

Answer 1

The correct option is D First falls and then rises to original position

When no sand will be poured, the center of gravity will be at the center of the hollow sphere. Thus when we start pouring sand it starts filling the bottom. Therefore during the initial state the mass is more concentrated at the bottom, center of gravity will start moving downwards from initial position. When the sphere is half filled then mass get accumulated on the top half 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.