JCECE Engineering JCECE Engineering Solved Paper-2002

  • question_answer
    If momentum of a certain body is increased by \[50%\], then increases in the KE of the body will be:

    A) \[25%\]                               

    B)  \[50%\]

    C)  \[100%\]                            

    D)  \[125%\]

    Correct Answer: D

    Solution :

    The relation between momentum \[(p)\] and kinetic energy \[(K)\] is                 \[p=\sqrt{2m\,\,K}\] When momentum is increased by \[50%\], then                 \[150=\sqrt{2mK'}\]                                        ? (i) and        \[100p=\sqrt{2mK}\]                                      ? (ii) From Eqs. (i) and (ii), we get                 \[\frac{150p}{100p}=\frac{\sqrt{K'}}{\sqrt{K}}\] \[\Rightarrow \]               \[{{\left( \frac{150}{100} \right)}^{2}}=\frac{K'}{K}\]        \[\Rightarrow \]               \[\frac{K'}{K}-1=\frac{9}{4}-1\] \[\Rightarrow \]               \[\frac{K'-K}{K}\times 100%=\frac{5}{4}\times 100=125%\]


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