Question

A stone tied to a string is rotated in a vertical plane. If mass of the stone is $m$, the length of the string is $r$ and the linear speed of the stone is $v$,When the stone is at its lowest point, then the tension in the string will be :

• A. $\frac{m{v}^2}{r}+mg$
• B. $\frac{m{v}^2}{r}-mg$
• C. $\frac{mv}{r}$
• D. $mg$

Answer 1

The correct option is A $\frac{m{v}^2}{r}+mg$

At the lowest point, as shown in the figure both mg and centrifugal force
$\frac{m{v}^2}{r}$will act in the same direction so,$T=mg+\frac{m{v}^2}{r}$