NEET Sample Paper NEET Sample Test Paper-14

  • question_answer
    A heavy circular disc whose plane is vertical is kept at rest on a rough inclined plane by a string parallel to the plane and touching the disc as shown in the figure. The disc starts to slip if:

    A) \[\mu <\frac{1}{2}\tan \alpha \]                    

    B) \[\mu >\frac{1}{2}\tan \alpha \]

    C) \[\mu <\tan \alpha \]               

    D) \[\mu >\tan \alpha \] 

    Correct Answer: A

    Solution :

    For rotational equilibrium, net torque is 0. Taking torque about the center of Disc,\[Tr=fr\]or \[T=f.\] For slipping \[T+f<mg\,\sin \alpha \] or \[2f<mg\sin \alpha \] or \[2\mu \,mg\,\cos \alpha <mg\sin \alpha \] or \[\mu <\frac{1}{2}\tan \alpha \] Hence, the correction option is [a].


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