Question

A stone of mass $m$ is tied to a string and is whirled in a horizontal circle of radius $r$ with angular velocity $w$. Which of the following relations is correct?

[take $T$ as the tension in the string]

• A. $T=m{w}^{2}r$
• B. $T\ge m{w}^{2}r$
• C. $T\le m{w}^{2}r$
• D. $T=w^{2}r$

Answer 1

The correct option is A $T=m{w}^{2}r$

For a stone whirled in a horizontal circle with the help of a string, the centripetal force is provided by the tension in the string and so it has to be equal to the tension in the string.

$\Rightarrow$ $T=m{w}^{2}r$