JEE Main & Advanced Sample Paper JEE Main Sample Paper-26

  • question_answer
    A cart is moving horizontal along a straight line with constant speed \[30\,m{{s}^{-1}}\]. A projectile is to fired from the moving cart in such a way that it will return to the cart after the cart has moved 80 m. At what speed (relative to the cart) must the projectile be fired?

    A)  \[10\,m{{s}^{-1}}\]                            

    B)  \[10\sqrt{8}\,m{{s}^{-1}}\]

    C)  \[\frac{40}{3}m{{s}^{-1}}\]                           

    D)  None     

    Correct Answer: C

    Solution :

    As seen from the cart the projectile moves vertically upwards and comes back. \[=\frac{S}{V}=\frac{80}{30}=\frac{8}{3}s\] Given \[u=?,\,\,v=0,\,\,a=-g\,=10\,m{{s}^{-2}}\] and \[t=\frac{8/3}{2}=\frac{4}{3}\,s\] Equation of motion v = u + at\[0=u-10\times \frac{4}{3}\,=\frac{40}{3}\,m{{s}^{-1}}\]

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