JEE Main & Advanced AIEEE Solved Paper-2006

  • question_answer
    A particle located at\[x=0\]at time\[t=0\], starts moving along the positive x-direction with a velocity v that varies as \[v=\alpha \sqrt{x}\]. The displacement of the particle varies with time as     AIEEE  Solved  Paper-2006

    A) \[{{t}^{2}}\]    

    B)                        \[t\]     

    C)        \[{{t}^{1/2}}\]                   

    D)        \[{{t}^{3}}\]

    Correct Answer: A

    Solution :

    The variation of the velocity is given as. \[v=\alpha \sqrt{x}\] We can write it as \[\frac{dx}{dt}=\alpha \sqrt{x}\]         \[\left( \because v=\frac{dx}{dt} \right)\] \[\Rightarrow \] \[\frac{dx}{\sqrt{x}}=\alpha dt\] Perform integration within the limit \[\int_{0}^{x}{\frac{dx}{\sqrt{x}}}=\int_{0}^{t}{\alpha \,dt}\] [\[\because \]at\[t=0,\text{ }x=0\]and let at any time t, particle be at\[x\]] \[\Rightarrow \]               \[\left. \frac{{{x}^{1/2}}}{1/2} \right|_{0}^{x}=\alpha t\]               \[\Rightarrow \]               \[{{x}^{1/2}}=\frac{\alpha }{2}t\] \[\Rightarrow \]               \[x=\frac{{{\alpha }^{2}}}{4}\times {{t}^{2}}\]\[\Rightarrow \]\[x\propto {{t}^{2}}\]


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