NEET AIPMT SOLVED PAPER SCREENING 2012

  • question_answer
                    The motion of a particle along a straight line is described by equation\[x=8+12\,t-{{t}^{3}}\]where, x is in metre and t in second. The retardation of the particle when its velocity becomes zero, is

    A) 24 \[\text{m}{{\text{s}}^{\text{-2}}}\]       

    B)        zero                      

    C)        6 \[\text{m}{{\text{s}}^{\text{-2}}}\]                     

    D)        12 \[\text{m}{{\text{s}}^{\text{-2}}}\]

    Correct Answer: D

    Solution :

    Given, \[x=8+12\,t-{{t}^{3}}\] We know \[v=\frac{dx}{dt}\]and\[a=\frac{dv}{dt}\]So,\[v=12-3\,{{t}^{2}}\]and\[a=-6t\] \[At\,t=2s\]\[v=0\]and\[a=-6t\]At \[t=2s\] \[a=-12\,m/{{s}^{2}}\] So, retardation of the particle \[=12\,\,m/{{s}^{2}}\].


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