NEET Sample Paper NEET Sample Test Paper-59

  • question_answer
    When a particle is projected at an angle to the horizontal, it has range R and time of flight \[{{t}_{1}}\]It the same projectile is projected with the same speed at another angle to have the same range and time of flight \[{{t}_{2}}\]then,

    A) \[{{t}_{1}}+{{t}_{2}}=\frac{2R}{g}\]             

    B) \[{{t}_{1}},{{t}_{2}}=\frac{2R}{g}\]

    C) \[{{t}_{1}}-{{t}_{2}}=\frac{2R}{g}\]               

    D) \[{{t}_{1}}\,{{t}_{2}}=\frac{2R}{g}\]

    Correct Answer: D

    Solution :

    [d] Let \[\theta \] and \[90{}^\circ -~\theta \]be the angles of projection for the same range \[{{t}_{1}}=\frac{2u\,\sin \,\theta }{g}\,and\,\,{{t}_{2}}=24\,Sin\,\frac{[90{}^\circ -\theta ]}{g}=\frac{2\,u\,Cos\,\theta }{g}\] \[{{t}_{1}}{{t}_{2}}=\frac{4{{u}^{2}}\,\sin \,\theta \,Cos\,\theta }{g}\,=\frac{2R}{g}\] \[\therefore \,\,\left[ R=\frac{2{{u}^{2}}\,Sin\theta \,Cos\theta }{g} \right]\]


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