NEET Physics NLM, Friction, Circular Motion NEET PYQ-NLM Friction Circular Motion

  • question_answer
    A bomb of mass 30 kg at rest explodes into two pieces of masses 18 kg and 12 kg. The velocity of 18 kg mass is 6 ms-1. The kinetic energy of the other mass is:                   [AIPMT (S) 2005]

    A) 256 J

    B) 486 J

    C) 524 J

    D) 324 J

    Correct Answer: B

    Solution :

    Key Idea: The linear momentum of exploding part will remain conserved.
                Applying conservation of linear momentum, we write,             \[{{m}_{1}}{{u}_{1}}={{m}_{2}}{{u}_{2}}\]
                Here,     \[{{m}_{1}}=18\,kg,\,{{m}_{2}}=12\,kg\]
                            \[{{u}_{1}}=6\,m{{s}^{-1}},\,\,{{u}_{2}}=\,\,?\]
                \[\therefore \]      \[18\times 6=12\,{{u}_{2}}\]     
                \[\Rightarrow \]   \[{{u}_{2}}=\frac{18\times 6}{12}=9\,m{{s}^{-1}}\]
                Thus, kinetic energy of 12 kg mass
                            \[{{K}_{2}}=\frac{1}{2}\,{{m}_{2}}u_{2}^{2}\]
                            \[=\frac{1}{2}\times 12\times {{(9)}^{2}}\]
                            \[=6\times 81\]
                            \[=\text{ }486J\]


You need to login to perform this action.
You will be redirected in 3 sec spinner