NEET Sample Paper NEET Sample Test Paper-79

  • question_answer
    The acceleration a of a particle moving in a straight line varies with displacement s according to relation \[\operatorname{a}= 2s\], then velocity of the particle vary with displacement as (given that velocity is zero at zero displacement)

    A)  s                                 

    B)  \[\sqrt{2}\,s\]

    C)  \[{{s}^{2}}\]                         

    D)  None of these

    Correct Answer: B

    Solution :

    As, \[\operatorname{a} = 2s\] \[\Rightarrow \,\,\,\,\frac{dv}{dt}=2s\] \[\Rightarrow \,\,\,\,\frac{dv}{ds}\,\frac{ds}{dt}=2s\] \[\Rightarrow \,\,\,\,\frac{dv}{ds}\,v=2s\] \[\Rightarrow \,\,\,\,v\,\,dv=2s\,\,ds\] \[\Rightarrow \,\,\,\,\int_{0}^{v}{vdv}\,\,=\,\,\int_{0}^{s}{2s\,\,ds}\,\] \[\Rightarrow \,\,\,\,\left[ \frac{{{v}^{2}}}{2} \right]_{0}^{v}\,\,\,=\,\,2\left[ \frac{{{s}^{2}}}{2} \right]_{0}^{s}\] \[\Rightarrow \,\,\,\,\frac{{{v}^{2}}}{2}={{s}^{2}}\,\,\,\Rightarrow \,\,\,v=\sqrt{2}\,s\]


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