JCECE Medical JCECE Medical Solved Paper-2014

  • question_answer
    A satellite is rotating around a planet in the orbit of radius r with time period T. If gravitational force changes according to \[{{r}^{5/2}},\]the \[{{T}^{2}}\]will be

    A) \[\propto {{r}^{3}}\]

    B)  \[\propto {{r}^{7/2}}\]

    C)  \[\propto {{r}^{9/2}}\]

    D)  \[\propto {{r}^{3/2}}\]

    Correct Answer: B

    Solution :

     \[\frac{GMm}{{{r}^{5/2}}}=\frac{m{{v}^{2}}}{r}\] \[{{v}^{2}}=\frac{GM}{{{r}^{3/2}}}\] \[{{T}^{2}}={{\left( \frac{2\pi r}{v} \right)}^{2}}\] \[=\frac{4{{\pi }^{2}}{{r}^{2}}}{GM/{{r}^{3/2}}}=\frac{4{{\pi }^{2}}{{r}^{7/2}}}{Gm}\] \[{{T}^{2}}\propto {{r}^{7/2}}\]


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