AMU Medical AMU Solved Paper-2012

  • question_answer
    A particle moves in a circular orbit of radius r fc under a central attractive force \[F=-\frac{k}{r},\,k\] is constant. The time period of its motion shall be proportional to

    A)  \[{{r}^{1/2}}\]                                  

    B)  r

    C)  \[{{r}^{3/2}}\]                                  

    D)  \[{{r}^{2/3}}\]

    Correct Answer: B

    Solution :

                     Central attractive force                 \[F=-\frac{k}{r}\]                 \[mr{{\omega }^{2}}=-\frac{k}{r}\]                 \[mr\,{{\left( \frac{2\pi }{T} \right)}^{2}}=-\frac{k}{T}\]                 \[\frac{mr4{{\pi }^{2}}}{{{T}^{2}}}=-\frac{k}{T}\]                                 \[{{T}^{2}}=\frac{m{{r}^{2}}4{{\pi }^{2}}}{k}\]                                 \[{{T}^{2}}\propto {{r}^{2}}\] or \[T\propto r\]


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