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9th Class Science Gravitation and Floatation Question Bank Gravitation Conceptive Objective Problems

  • question_answer
    If R is the radius of the earth, the height above the surface of the earth where the weight of the body is 36% less than its value on the surface of the earth

    A)  \[\frac{4R}{5}\]                                               

    B)  \[\frac{R}{5}\]

    C)  \[\frac{R}{6}\]                                 

    D)  \[\frac{R}{4}\]

    Correct Answer: D

    Solution :

       \[{{w}_{1}}=\frac{6400}{100}\Rightarrow {{g}_{1}}=\frac{64g}{100},={{g}_{1}}=\frac{g{{R}^{2}}}{{{(R+h)}^{2}}}\] \[\Rightarrow \frac{64g}{100}=\frac{{{g}_{1}}}{\left( 1+\frac{h}{R} \right)}\Rightarrow 8h=2R\Rightarrow h=\frac{R}{4}\] \[8(R+h)=10R\Rightarrow 8h=2R\Rightarrow h=\frac{R}{4}\]


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