A metal coin of mass 5   g and radius 1   c m is fixed to a thin stick A B of negligible mass as…

A metal coin of mass $5\mathrm{ }\mathrm{g}$ and radius $1\mathrm{ }\mathrm{c}\mathrm{m}$ is fixed to a thin stick $\mathrm{A}\mathrm{B}$ of negligible mass as shown in the figure. The system is initially at rest. The constant torque, that will make the system rotate about $\mathrm{A}\mathrm{B}$ at $25$ rotations per second in $5\mathrm{ }\mathrm{s}$ , is close to:

1. $1.6\times {10}^{-5}\mathrm{ }\mathrm{N}\mathrm{ }\mathrm{m}$
2. $2.0\times {10}^{-5}\mathrm{ }\mathrm{N}\mathrm{ }\mathrm{m}$
3. $7.9\times {10}^{-6}\mathrm{ }\mathrm{N}\mathrm{ }\mathrm{m}$
4. $4.0\times {10}^{-6}\mathrm{ }\mathrm{N}\mathrm{ }\mathrm{m}$

Solution

Asked in: JEE Main 2019 (10 Apr Shift 2)

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