CET Karnataka Medical CET - Karnataka Medical Solved Paper-2003

  • question_answer
    For a given velocity, a projectile has the same range R for two angles of projection if \[{{t}_{1}}\]and \[{{t}_{2}}\]are the time of flight in the two cases, then:

    A)  \[{{t}_{1}}{{t}_{2}}\propto R\]

    B)  \[{{t}_{1}}{{t}_{2}}\propto {{R}^{2}}\]

    C)  \[{{t}_{1}}{{t}_{2}}\propto \frac{1}{{{R}^{2}}}\]

    D)  \[{{t}_{1}}{{t}_{2}}\propto \frac{1}{R}\]

    Correct Answer: A

    Solution :

    \[{{t}_{1}}=\frac{2u\,\sin \alpha }{g}\] \[{{t}_{2}}=\frac{2u\,\sin (90-\alpha )}{g}\] So,    \[{{t}_{1}}\times {{t}_{2}}=2\frac{{{u}^{2}}}{{{g}^{2}}}\sin 2\alpha \] or \[{{t}_{1}}\times {{t}_{2}}=\frac{2R}{g}\] \[\left( \because \,\,R=\frac{{{u}^{2}}\sin 2\alpha }{g} \right)\] \[{{t}_{1}}\times {{t}_{2}}\propto R\]


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