A stone tied to a string is rotated with a uniform speed in a vertical plane. If mass of the stone is `m`, the length of the string is `r` and linear speed of the stone is `v` when the stone is at its lowest point, then the tension in the string will be
(g= acceleration due to gravity)

Options

A. `mg`
B. `mv^(2)//r`
C. `(mv^(2)//r)-mg`
D. `(mv^(2)//r)+mg`

Answer

D

Explanation

We know that centrigugal force `=mv^(2)//r`
When the stone is the lowest point, them Tension in string=centrifugal force+weight of stone
:. `T=(mv^(2))/(r)+mg` .