A weightless thread can support tension up

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A weightless thread can support tension upto $30 \,N$. A stone of mass $0.5 \,kg$ is tied to it and is revolved in a circular path of radius $2 \,m$ in a vertical plane. If $g = 10m/{s^2}$, then the maximum angular velocity of the stone will be ........ $rad/s$

A

$5$

B

$\sqrt {30}$

C

$\sqrt {60}$

D

$10$

A weightless thread can support tension upto $30 \,N$. A stone of mass $0.5 \,kg$ is tied to it and is revolved in a circular path of radius $2 \,m$ in a vertical plane. If $g = 10m/{s^2}$, then the maximum angular velocity of the stone will be ........ $rad/s$

${T_{\max }} = m\omega _{^{\max }}^2r + mg$

$⇒$  $\frac{{{T_{\max }}}}{m} = {\omega ^2}r + g$

$⇒$ $\frac{{30}}{{0.5}} - 10 = {\omega ^2}_{\max }r$

$⇒$ ${\omega _{\max }} = \sqrt {\frac{{50}}{r}} = \sqrt {\frac{{50}}{2}} = 5\,rad/s$