CET Karnataka Engineering CET - Karnataka Engineering Solved Paper-2001

  • question_answer
    A satellite with kinetic energy\[{{E}_{k}}\]is revolving round the earth in a circular orbit. How much more kinetic energy should be given to it so that it may just escape into outer space.

    A)  \[{{E}_{k}}\]                                     

    B) \[2{{E}_{k}}\]

    C)  \[\frac{1}{2}{{E}_{k}}\]                

    D) \[3{{E}_{k}}\]

    Correct Answer: A

    Solution :

    If \[{{\upsilon }_{0}}\]be the orbital speed of the satellite of mass \[m,\]then \[{{E}_{k}}=\frac{12}{2}m\upsilon _{\upsilon }^{2}\] If \[{{\upsilon }_{e}}\]is the escape velocity, then we have \[{{\upsilon }_{e}}=\sqrt{2}{{\upsilon }_{0}}\] Thus kinetic energy required to escape \[E{{'}_{K}}=\frac{1}{2}m\upsilon _{e}^{2}=\frac{1}{2}m{{(\sqrt{2}{{\upsilon }_{0}})}^{2}}\] \[=2\left( \frac{1}{2}m\upsilon _{0}^{2} \right)=2{{E}_{K}}\] Therefore, additional kinetic energy required \[=2{{E}_{K}}-{{E}_{K}}={{E}_{K}}\]


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