Physics Two Dimensional Motion Question 173
Question: A ball rolls off to the top of a staircase with a horizontal velocity u m/s. If the steps are h meter high and b meter wide, the ball will hit the edge of the nth step, if
Options:
A) $ n=\frac{2hu}{gb^{2}} $ B)$ n=\frac{2hu^{2}}{gb} $ C) $ n=\frac{2hu^{2}}{gb^{2}} $ D)$ n=\frac{hu^{2}}{gb^{2}} $
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Answer:
Correct Answer: C
Solution:
[c] If the ball hits the nth step, then the horizontal distance traversed = nh. Here, the velocity along the horizontal direction = u. Initial velocity along the vertical direction = 0. So $ nb=ut $ …(i) $ nh=0+\frac{1}{2}gt^{2} $ …(ii). From $ t=\frac{nb}{v}, $ putting in eq. (ii) $ nh=\frac{1}{2}g\times {{( \frac{nb}{u} )}^{2}} $ or $ n=\frac{2hu^{2}}{gb^{2}} $
BETA
