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 at the lowest point will be

• A. Maximum
• B. Minimum
• C. Neither maximum nor minimum
• D. Zero

Answer 1

Answer: (A)

Maximum

Centripetal force on the stone $=\frac{m{v}^2}{r}$

At the lowest point, Tension in the string, $T_1$ = centripetal force - weight of the stone

At other points, Tension in the string, $T_2$ = centripetal force - component of weight of the stone along the direction of the string

Hence, $T_1>T_2$