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

  • question_answer
    If the radius of the earth is 6400 km, the height above the surface of the earth, where the value of acceleration to gravity will be 1 % of the value on the surface of the earth

    A)  6400 km             

    B)  64 km

    C)  57600 km      

    D)  2500 km

    Correct Answer: C

    Solution :

      \[{{g}_{1}}=\frac{g}{100},{{g}_{1}}=\frac{g{{R}^{2}}}{{{(R+h)}^{2}}}\]\[\Rightarrow \frac{g}{100}=\frac{g}{{{\left( 1+\frac{h}{R} \right)}^{2}}}\] \[\Rightarrow {{\left( 1+\frac{h}{R} \right)}^{2}}=100\Rightarrow 1+\frac{h}{R}=10\] \[\Rightarrow h=9R=9\times 6400=57,600\,km\]              


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