NEET AIPMT SOLVED PAPER 1999

  • question_answer
                    Two bodies with kinetic energies in the ratio 4 : 1 are moving with equal linear momentum. The ratio of their masses is:                                                                                                                                                           

    A)                 1 : 2                       

    B)                 1 : 1       

    C)                 4 : 1   

    D)                 1 : 4

    Correct Answer: D

    Solution :

                    The kinetic energy of a body of mass m moving with velocity v is                 \[K=\frac{1}{2}\,m{{v}^{2}}\]                 Its linear momentum                 \[p=mv\]                 \[\therefore \]  \[K=\frac{1}{2m}\,{{(mv)}^{2}}\]                 \[orK=\frac{{{p}^{2}}}{2m}\]                 \[\therefore \frac{{{K}_{1}}}{{{K}_{2}}}=\frac{p_{1}^{2}}{2{{m}_{1}}}\times \frac{2{{m}_{2}}}{p_{2}^{2}}\]                 but \[{{p}_{1}}={{p}_{2}}\] (given)                 \[So,\frac{{{K}_{1}}}{{{K}_{2}}}=\frac{{{m}_{2}}}{{{m}_{1}}}\]                 \[or\frac{{{m}_{1}}}{{{m}_{2}}}=\frac{{{K}_{2}}}{{{K}_{1}}}=\frac{1}{4}\]                 Thus,     \[{{m}_{1}}:{{m}_{2}}=1:4\]


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