The bob of a simple pendulumis a ball full of water. If a fine hole is made in the bottom of the ball, what will be its effect on the time period of the pendulum?

Explanation

When a hole is made in the bottom of a ball full of water, the water flows out slowly through the hole. As the water flows out of the ball, the centre of mass of the system will first move down and then will come up. Due to it, the equivalent length of pendulum L and hence time period T first increases, reaches a maximum value and then decreases till it beomes equal to its intial value.