NEET AIPMT SOLVED PAPER MAINS 2012

  • question_answer
    A car of mass m starts from rest and accelerates so that the instantaneous power delivered to the car has a constant magnitude \[{{p}_{0}}.\]The instantaneous velocity of this car is proportional to

    A) \[{{t}^{2}}{{p}_{0}}\]                     

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

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

    D) \[t/\sqrt{m}\]

    Correct Answer: B

    Solution :

    Power \[{{P}_{0}}=Fv\] \[=\left( m\frac{dv}{dt} \right)v\] \[=mv\frac{dv}{dt}\] Integrating both sides \[\int_{{}}^{{}}{{{p}_{0}}dt=\int_{{}}^{{}}{mv\,dv}}\] \[{{p}_{0}}t=\frac{m{{v}^{2}}}{2}\] \[{{v}^{2}}=\frac{2{{p}_{0}}t}{m}\] \[v\propto {{t}^{1/2}}\]


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