JEE Main & Advanced AIEEE Solved Paper-2004

  • question_answer
    A projectile can have the same range R for two angles of projection. If\[{{T}_{1}}\]and\[{{T}_{2}}\]are the times of flights in the two cases, then the product of the two times of flights is directly proportional to     AIEEE  Solved  Paper-2004  

    A) \[\frac{1}{{{R}^{2}}}\]    

    B)                        \[\frac{1}{R}\]                  

    C)        R            

    D)        \[{{R}^{2}}\]

    Correct Answer: C

    Solution :

                    We know that range of projectile is same for complementary angles i.e., for\[\theta \]and\[(90{}^\circ -\theta ).\] \[\therefore \] \[{{T}_{1}}=\frac{2u\sin \theta }{g}\] \[{{T}_{2}}=\frac{2u\sin ({{90}^{o}}-\theta )}{g}=\frac{2u\cos \theta }{g}\] and \[R=\frac{{{u}^{2}}\sin 2\theta }{g}\] Therefore, \[{{T}_{1}}{{T}_{2}}=\frac{2u\sin \theta }{g}\times \frac{2u\cos \theta }{g}\]                                 \[=\frac{2{{u}^{2}}(2\sin \theta \cos \theta )}{{{g}^{2}}}\]                                 \[=\frac{2{{u}^{2}}(\sin 2\theta )}{{{g}^{2}}}=\frac{2R}{g}\] \[\therefore \]  \[{{T}_{1}}{{T}_{2}}\propto R\] 


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