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Question
A hollow sphere filled with water is used as the bob of a pendulum. Assume that the equation for simple pendulum is valid with the distance between the point of suspension and centre of mass of the bob acting as the effective length of the pendulum. If water slowly leaks out of the bob, how will the time period vary?
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Solution
The time period of a pendulum depends on the length and is given by the relation , \[T = 2\pi\sqrt{\frac{l}{g}}\]
As the effective length of the pendulum first increases and then decreases, the time period first increases and then decreases.
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