JEE Main & Advanced Physics Two Dimensional Motion Question Bank Mock Test - Motion in Two Dimension

  • question_answer
    A stone projected with a velocity \[u\] at an angle \[\theta \] With the horizontal reaches maximum height \[{{H}_{1}}\] When it is projected with velocity u at an angle \[(\frac{\pi }{2}-\theta )\] with the horizontal, it reaches maximum height \[{{H}_{2}}\]. The relation between the horizontal range R of the projectile, \[{{H}_{1}}\]and \[{{H}_{2}}\]is

    A) \[R=4\sqrt{{{H}_{1}}{{H}_{2}}}\]

    B) \[R=\,4({{H}_{1}}-{{H}_{2}})\]

    C) \[R=\,4({{H}_{1}}+{{H}_{2}})\]

    D) \[R=\,\frac{{{H}^{2}}_{1}}{{{H}^{2}}_{2}}\]

    Correct Answer: A

    Solution :

    [a] \[{{H}_{1}}=\frac{{{u}^{2}}{{\sin }^{2}}\theta }{2g}and\,\,\,{{H}_{2}}=\frac{{{u}^{2}}{{\sin }^{2}}(90-\theta )}{2g}=\frac{{{u}^{2}}{{\cos }^{2}}\theta }{2g}\] \[{{H}_{1}}{{H}_{2}}=\frac{{{u}^{2}}{{\sin }^{2}}\theta }{2g}\times \frac{{{u}^{2}}{{\cos }^{2}}\theta }{2g}\] \[=\frac{{{({{u}^{2}}sin2\theta )}^{2}}}{16{{g}^{2}}}=\frac{{{R}^{2}}}{16}\] \[[\therefore R=4\sqrt{{{H}_{1}}{{H}_{2}}}\]


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