J & K CET Medical J & K - CET Medical Solved Paper-2004

  • question_answer
    If the velocity of a particle is given by \[v={{(180-16\times )}^{1/2}}m/s,\] then its acceleration will be :

    A)  zero                                     

    B)  \[8m/{{s}^{2}}\]

    C)  \[-8\text{ }m/{{s}^{2}}\]                                             

    D)  \[4\text{ }m/{{s}^{2}}\]

    Correct Answer: C

    Solution :

                    Rate of change of velocity gives acceleration. Given, \[v={{(180-16x)}^{1/2}}\] Using\[\frac{d}{dx}{{x}^{n}}=n{{x}^{n-1}},\], we have                 \[{{v}^{2}}=180-16x\] \[\therefore \]Differentiating with respect to t, we get                 \[2v=\frac{dv}{dt}=0-16\frac{dx}{dt}\]                 \[2v\frac{dv}{dt}=-16v\] \[\Rightarrow \]               \[\frac{dv}{dt}=-8\] Hence, particle decelerates at the rate of\[8\text{ }m/{{s}^{2}}\].


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