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A ball rolls offthe top of a stairway with a horizontalvelocity of magnitude 1.8 ms1. The steps are 0.20m high and 0.20 m wide. The step which the ballhits first is -(A) first(B) second(D) fourth(C) third |
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Answer» let the no. of step be n we have to find the horizontal range = n(0.20)n*(0.20) = (1.8)t => t = n(0.20)/1.8 now n(0.20) = 1/2gt² putting the value of t in 2nd equation..=> n(0.20)*2 = g(n*(0.20))²/1.8²)=> 2*1.8*1.8 = 10*(n*(0.20)=> n = (2*1.8*1.8)/2 = 3.24 since n = 3.24 , so it will cross third stepso the value will br greater that 3rd step 4th step.. is the answer. |
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