JEE Main & Advanced Physics Two Dimensional Motion Question Bank Self Evaluation Test - Motion in a Plane

  • question_answer
    The equation of trajectory of projectile is given by\[y=\frac{x}{\sqrt{3}}-\frac{\text{g}{{\text{x}}^{2}}}{20}\], where x and y are in meter. The maximum range of the projectile is

    A) \[\frac{8}{3}\text{ m}\] 

    B)        \[\frac{4}{3}\text{ m}\]

    C) \[\frac{3}{4}\text{ m}\] 

    D)        \[\frac{3}{8}\text{ m}\]

    Correct Answer: B

    Solution :

    [b] Comparing the given equation with the equation of trajectory of a projectile, \[y=x\,\,\tan \theta -\frac{\text{g}{{\text{x}}^{2}}}{2{{\text{u}}^{2}}{{\cos }^{2}}\theta },\text{ }\] we get, \[\text{tan}\theta \,\text{=}\,\,\frac{1}{\sqrt{3}}\Rightarrow \theta =30{}^\circ \] and \[2{{\text{u}}^{2}}{{\cos }^{2}}\theta =20\Rightarrow {{\text{u}}^{2}}=\frac{20}{2{{\cos }^{2}}\theta }=\frac{40}{3}\] Now, \[{{\text{R}}_{\max }}=\frac{{{\text{u}}_{2}}}{\text{g}}=\frac{40}{3\times 10}=\frac{4}{3}\text{m}\]


You need to login to perform this action.
You will be redirected in 3 sec spinner