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9th Class Science Work and energy Question Bank Work, Energy and Power

  • question_answer
    A ball is allowed to fall from a height of 10 there is 40% loss of energy due to impact, after one impact ball will go upto

    A)  10 m              

    B)         8 m              

    C)  4m                 

    D)         6m  

    Correct Answer: D

    Solution :

                    \[mg{{h}_{2}}=mg{{h}_{1}}\times \frac{60}{100}\] Since ball losses \[40%\] of its energy, therefore it is left with \[60%\] of energy                 \[{{h}_{2}}={{h}_{1}}\times \frac{60}{100}=\frac{10\times 60}{100}m=\mathbf{6}\,\,\mathbf{m}\]


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