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9th Class Science Work and energy Question Bank Work, Energy and Power

  • question_answer
    The displacement \[x\] of a particle moving in one dimension, under the action of a constant force, is related to the time t by the equation,\[t=\sqrt{x}+3\]where \[x\] is in metres and t in seconds. The displacement of the particle when its velocity is zero, is

    A)  0                              

    B)         6 m

    C)  12m                     

    D)         18m

    Correct Answer: A

    Solution :

     Given,  \[t=\sqrt{x}+3\] \[\Rightarrow \]                               \[x={{(t-3)}^{2}}\]                            ? (i) \[\therefore \]                  \[v=\frac{dx}{dt}=2(t-3)=0\] \[\Rightarrow \]                               \[t=\sec \] Putting it in equation (i), we get                                 \[x={{(3-3)}^{2}}=\mathbf{0}\]


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