You can see the similar thread here, actually it has given more appropriate explanation than me, but still the thread is unsolved.
https://www.physicsforums.com/showthread.php?t=389744
1. 1. Homework Statement :
How to calculate minimum time period 't' required to complete a vertical circular motion by a cone filled with water, so that the water doesn't fall?2. Homework Equations :
v^2 = gR * [ 3 + 2 cos (theta) ] obtained by applying law of conservation of energy.
3. 3...