NEET Sample Paper NEET Sample Test Paper-1

  • question_answer The average force necessary to stop a bullet of mass \[20g\] and \[250\text{ }m/s\] as it penetrates wood to a distance of \[12cm,\] is:

    A)  \[5.2\times {{10}^{3}}N\]        

    B)  \[4.2\times {{10}^{3}}N\]

    C)  \[3.2\times {{10}^{3}}N\]              

    D)  \[2.2\times {{10}^{3}}N\]

    Correct Answer: A

    Solution :

    Here mass of the bullet \[=20g=0.02\,kg\] Speed \[\upsilon =250\,m/s\]. Distance \[s=12\,cm=0.12\,m\] \[\therefore \] Loss of kinetic energy                                          \[=\frac{1}{2}\,m{{\upsilon }^{2}}\]                 \[=\frac{1}{2}\times 0.02\times {{(250)}^{2}}\]                 \[=625\,J\] Now from energy theorem, we have             \[F\times 0.12=625\] \[\Rightarrow \]               \[F=\frac{625}{0.12}\] \[\Rightarrow \]               \[F=5.2\times {{10}^{3}}N\]


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