JEE Main & Advanced Physics Work, Energy, Power & Collision / कार्य, ऊर्जा और शक्ति Question Bank Self Evaluation Test - Work, Energy and Power

  • question_answer
    If the momentum of a body is increased by 50%, then the percentage increase in its kinetic energy

    A) 50%

    B) 100%

    C) 125%

    D) 200%

    Correct Answer: C

    Solution :

    [c] Initial momentum \[\left( {{p}_{1}} \right)=p,\] Final momentum \[\left( {{p}_{2}} \right)= 1.5\]p and initial kinetic energy\[\left( {{K}_{1}} \right)=K\]. Kinetic energy \[\left( K \right) = \frac{{{p}^{2}}}{2m}\propto {{p}^{2}}\] Or,        \[\frac{{{K}_{1}}}{{{K}_{2}}} = {{\left( \frac{{{p}_{1}}}{{{p}_{2}}} \right)}^{2}}={{\left( \frac{p}{1.5p} \right)}^{2}}=\frac{1}{2.25}\] or,        \[{{K}_{2}}=2.25K.\] Therefore, increase in kinetic energy is 2.25 \[KK=1.25\text{ }K\text{ }or\text{ }125%.\]


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