First slide
Release from certain height
Question

 A stone is dropped from the 25th storey of a multistoried building and it reaches the ground in 5 s. In the first second, it passes through how many storeys of the building? (g = 10 ms-2)

Moderate
Solution

Suppose h be the height of each storey. Then
25 h=0+12×10×t2=12×10×52 or h=5 m
In first second, let the stone passes through n storey. 
 So n×5=12×10×(1)2   or   n=1

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