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

  • question_answer
    A body weights 63N on the surface of the Earth. At a height h above the surface of Earth, its weight is 28N while at a depth h below the surface of Earth, the weight is 31.5N. The value of h is

    A)  0.4 R                    

    B)  0.5 R  

    C)  0.8 R                    

    D)  R

    Correct Answer: B

    Solution :

       \[m{{g}_{d}}=mg\left[ 1-\frac{d}{R} \right]\] \[31.5=63\left[ 1-\frac{d}{R} \right]\,\,or\,\,1-\frac{d}{R}=\frac{31.5}{63}=\frac{1}{2}\,\,or\] \[\frac{d}{\operatorname{R}}=1-\frac{1}{2}=\frac{1}{2}\,\,or\,\,2d=R\,\,or\,\,d-\frac{R}{2}=0.5\,R\]


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