NEET Physics Rotational Motion NEET PYQ-Rotational Motion

  • question_answer
    A wheel having moment of inertia \[2\text{ }kg-{{m}^{2}}\] about its vertical axis, rotates at the rate of 60 rpm about this axis. The torque which can stop the wheel's rotation in one minute would be: [AIPMT (S) 2004]

    A) \[\frac{2\pi }{15}N-m\]

    B) \[\frac{\pi }{12}N-m\]

    C) \[\frac{\pi }{15}N-m\]

    D) \[\frac{\pi }{18}N-m\]

    Correct Answer: C

    Solution :

    Given:   \[I=2kg-{{m}^{2}},\,\,{{\omega }_{0}}=\frac{60}{60}\times 2\pi \,rad/s,\]
                            \[\omega =0,\,\,t=60\,s\]
    The torque required to stop the wheel’s rotation is
    \[\tau =I\,\alpha =I\left( \frac{{{\omega }_{0}}-\omega }{t} \right)\]
                \[\therefore \]      \[\tau =\frac{2\times 2\pi \times 60}{60\times 60}=\frac{\pi }{15}N-m\]


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