JEE Main & Advanced Physics NLM, Friction, Circular Motion Question Bank Graphical Questions

  • question_answer
    A particle of mass m, initially at rest, is acted upon by a variable force F for a brief interval of time T. It begins to move with a velocity u after the force stops acting. F is shown in the graph as a function of time. The curve is a semicircle.

    A)                                 \[u=\frac{\pi F_{0}^{2}}{2m}\]                

    B)                                    \[u=\frac{\pi {{T}^{2}}}{8m}\]                

    C)                                 \[u=\frac{\pi {{F}_{0}}T}{4m}\]                

    D)                                    \[u=\frac{{{F}_{0}}T}{2m}\]

    Correct Answer: C

    Solution :

                                    Initially particle was at rest. By the application of force its momentum increases. Final momentum of the particle \[=\]Area of F - t graph Þ \[mu=\]Area of semicircle                                 \[mu=\frac{\pi \ {{r}^{2}}}{2}\]\[=\frac{\pi \ {{r}_{1}}{{r}_{2}}}{2}\]\[=\frac{\pi \ ({{F}_{0}})\ (T/2)}{2}\]Þ\[u=\frac{\pi \ {{F}_{0}}T}{4m}\]                


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