Question 11 Mark
A stone is fastened to one end of a string and is whirled in a vertical circle of radius R. Find the minimum speed the stone can have at the highest point of the circle.
Answer
View full question & answer→At the highest point of a vertical circle
$\frac{\text{mv}^2}{\text{R}}=\text{mg}$
$\Rightarrow\text{v}^2=\text{Rg}\Rightarrow\text{v}=\sqrt{\text{Rg}}$