JEE Main & Advanced Physics NLM, Friction, Circular Motion JEE PYQ - NLM Friction Circular Motion

  • question_answer
    A bomb of mass 16 kg at rest explodes into two pieces of masses 4 kg and 12 kg. The velocity of the 12 kg mass is\[4\text{ }m{{s}^{-1}}\]. The kinetic energy of the other mass is                [AIEEE 2006]

    A) 144 J

    B) 288 J

    C) 192 J

    D) 96 J

    Correct Answer: B

    Solution :

    [b] Here, momentum of the system is remaining conserved as external force is acting on the bomb (system).   
    Initial momentum (before explosion)
    = Final momentum (after explosion)
    Let velocity of 4 kg mass be v m/s. From momentum conservation, we can say that its direction is opposite to velocity of 12 kg mass.
    From           \[{{\vec{P}}_{i}}={{\vec{P}}_{f}}\]
    \[\Rightarrow \] \[0=12\times 4-4\times v\] \[\Rightarrow \] \[v=12\,m/s\]
    KE of 4kg mass \[=\frac{4\times {{(12)}^{2}}}{2}=288\,J\]

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