A can filled with water is revolved in a vertical circle of radius r with constant speed and water just does not fall down. The time period of revolution is (g= acceleration due to gravity)

Step-by-step solution

For water not to fall off the can, then centrifugal force must balance the weight of water, m v^2 r m g Minimum speed of the can so that water does not fall down is given by, v= r g Time period of revolution, T= 2 r v =2 r g