Question

A stone tied to a string is rotated in a vertical circle. The minimum speed with which the stone has to be rotated in order to complete the circle :

• A. decreases with increasing the mass of the stone
• B. is independent of the mass of the stone
• C. decreases with increasing the length of the string
• D. is independent of the length of the string

Answer 1

The correct option is B is independent of the mass of the stone

We can use the conservation of energy equation to find minimum speed required for completing the circle

$V=\sqrt{5Rg}$ (this speed is minimum speed required for completing the circle)
i.e. independent of the mass of the stone.