NEET Sample Paper NEET Sample Test Paper-4

  • question_answer
    A particle of mass m starts from rest and moves in a circular path of radius R with a uniform angular acceleration\[\propto \]. The kinetic energy of the particle after n revolutoins is:

    A)  \[n\propto m\,{{R}^{2}}\]              

    B)  \[2\pi n\propto n{{R}^{2}}\]

    C)  \[\frac{1}{2}\,mn\propto {{R}^{2}}\]                   

    D)  \[mn\propto {{R}^{2}}\]

    Correct Answer: B

    Solution :

    For uniform angular acceleration in a circular path, the angular speed is given by \[{{\omega }^{2}}={{\omega }^{2}}_{0}+2\alpha \theta =0+2\alpha \,(2\pi n)\] Kinetic energy of the particle \[KE=\frac{1}{2}m\]  \[{{(R\omega )}^{2}}=\frac{1}{2}m{{R}^{2}}\,(4a\,\pi n)\] \[=2\pi nm\,\alpha {{R}^{2}}\]


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