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9th Class Science Gravitation and Floatation Question Bank Gravitation

  • question_answer
    At what height, is the value of g half that on the surface of earth? (R = radius of the earth)

    A) \[0.\text{414R}\]               

    B)  R

    C)  2R                         

    D)         3.5R

    Correct Answer: A

    Solution :

            \[g'=\frac{g{{R}^{2}}}{{{r}^{2}}}=\frac{g}{2}\] \[\Rightarrow \]       \[{{r}^{2}}=2{{R}^{2}}\] \[\Rightarrow \]               \[r=R\sqrt{2}=R+h\] \[\Rightarrow \]               \[h=R(\sqrt{2}-1)\]                    \[=R(1.414-1)\]                   \[=\mathbf{0}\mathbf{.414}\,\,\mathbf{R}\].


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