Question

A hollow metal sphere is filled with water through a small hole in it. It is hung by a long thread and is made to oscillate. Water slowly flows out of the hole at the bottom. Select the correct variation of its time period

• A. The period will go on increasing till the sphere is empty
• B. The period will go on decreasing till the sphere is empty
• C. The period will not be affected at all
• D. The period will increase first, then decrease to initial value till the sphere is empty

Answer 1

Answer: (D)

As the water level goes down, the distance of C.O.M.
From point of oscillation $P$ keeps increasing.
Since $T=2\pi \sqrt{\frac{l}{g}}$
The time period of pendulum keep increasing.