AMU Medical AMU Solved Paper-2007

  • question_answer
    A thin rod of mass m and length 21 is made to rotate about an axis passing through its centre and perpendicular to it. If its angular velocity changes from 0 to \[\omega \]time t, the torque acting on it is

    A)  \[\frac{m{{l}^{2}}\omega }{12t}\]                           

    B)  \[\frac{m{{l}^{2}}\omega }{3t}\]

    C)   \[\frac{m{{l}^{2}}\omega }{t}\]                               

    D)  \[\frac{4m{{l}^{2}}\omega }{3t}\]

    Correct Answer: B

    Solution :

                     Since,   \[\tau =I\alpha \] \[\Rightarrow \]               \[\tau =\left[ \frac{m\,{{(2l)}^{2}}}{12} \right]\left( \frac{\omega }{t} \right)\] \[\Rightarrow \]               \[\tau =\frac{m\times 4{{l}^{2}}\times \omega }{12\times t}\] \[\Rightarrow \]               \[\tau =\frac{4m{{l}^{2}}\omega }{12t}=\left( \frac{m{{l}^{2}}\omega }{3t} \right)\]


You need to login to perform this action.
You will be redirected in 3 sec spinner