CMC Medical CMC-Medical VELLORE Solved Paper-2011

  • question_answer
    A satellite with kinetic energy E revolving round the earth in a circular orbit. The minimum additional KE required for it to escape into outer space is

    A)  \[\sqrt{2}E\]                     

    B)  2 E

    C)  \[E/\sqrt{2}\]                   

    D)  E

    E)  \[\frac{E}{2}\]

    Correct Answer: B

    Solution :

                    When a satellite is orbitting close to earth, its orbital velocity, \[{{v}_{o}}=\sqrt{\frac{GM}{R}}\] escape velocity, \[{{v}_{e}}=\sqrt{\frac{2GM}{R}}\] Here, kinetic energy, \[E=\frac{1}{2}mv_{o}^{2}=\frac{1}{2}m\frac{GM}{R}\] KE required to escape, \[{{E}_{1}}=\frac{1}{2}mv_{e}^{2}=\frac{1}{2}m\left( \frac{2GM}{R} \right)=2E\] \[\therefore \] Additional KE required\[=2E-E=E\]


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