AFMC AFMC Solved Paper-2011

  • question_answer
    A ball rolls off the top of stairway with a horizontal velocity of magnitude 1.8 m/s. The slops are 0.20 m high and 0.20 m wide. Which step will the ball hit first?

    A) First                                      

    B) Second

    C) Third                                     

    D) Fourth

    Correct Answer: D

    Solution :

    Given, \[x=0.20\text{ }m,\text{ }y=0.20\text{ }m,\text{ }u=1.8\text{ }m/s.\]Let the ball strike the nth step of stairs. Vertical distance travelled \[=ny=n\times 0.20=\frac{1}{2}g{{t}^{2}}\] Horizontal distance travelled, \[nx=ut\] or          \[t=\frac{nx}{u}\]                  \[\therefore \]      \[ny=\frac{1}{2}g\times \frac{{{n}^{2}}{{x}^{2}}}{{{u}^{2}}}\] or \[n=\frac{2{{u}^{2}}}{g}\frac{y}{{{x}^{2}}}=\frac{2\times {{(1.8)}^{2}}\times 0.20}{9.8\times {{(0.20)}^{2}}}=3.3=4\]


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