JEE Main & Advanced JEE Main Paper (Held On 19 April 2014)

  • question_answer
    A ball of mass 160 g is thrown up at an angle of \[60{}^\circ \] to the horizontal at a speed of \[10m{{s}^{-1}}.\]The angular momentum of the ball at the highest point of the trajectory with respect to the point from which the ball is thrown is nearly \[(g=10m{{s}^{-2}})\]     JEE Main Online Paper (Held On 19 April 2016)

    A) \[1.73kg{{m}^{2}}/s\]                    

    B) \[3.0kg{{m}^{2}}/s\]

    C) \[3.46kg{{m}^{2}}/s\]                    

    D) \[6.0kg{{m}^{2}}/s\]

    Correct Answer: C

    Solution :

    Given : m = 0.160 kg \[\theta ={{60}^{o}}\]                                    v = 10 m/s Angular momentum \[L=\overset{\to }{\mathop{r}}\,\times m\overset{\to }{\mathop{v}}\,\] \[=Hmv\cos \theta \] \[=\frac{{{v}^{2}}{{\sin }^{2}}\theta }{2g}\cos \theta \]  \[\left[ H=\frac{{{v}^{2}}{{\sin }^{2}}\theta }{2g} \right]\] \[=\frac{{{10}^{2}}\times {{\sin }^{2}}{{60}^{o}}\times \cos {{60}^{o}}}{2\times 10}\] \[=3.46kg\,{{m}^{2}}/s\]


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