2. Solved Papers
  3. BHU PMT

BHU PMT BHU PMT (Screening) Solved Paper-2006

  • question_answer
    A cart is moving horizontally along a straight line with constant speed 30 m/s. A projectile is to be fired form 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? (Take\[g=10\text{ }m/{{s}^{2}}\])

    A)  10 m/s                                

    B)  \[10\,m/s\]

    C)  \[\frac{40}{3}m/s\]                       

    D)  None of these

    Correct Answer: C

    Solution :

                     As seen from the cart, the projectile moves vertically upward and comes back. The time taken by cart to cover 80 m                 \[\frac{s}{v}=\frac{80}{30}=\frac{8}{3}s\] For    a    projectile    going    upward, \[a=-g=-10/m{{s}^{-2}},v'=0\] And        \[t=\frac{8/3}{2}=\frac{4}{3}s\] \[\therefore \]  \[v'=u+at\] Or           \[0=u-10\times \frac{4}{3}\] Or           \[u=\frac{40}{5}m{{s}^{-1}}\]


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