A stone falls from a building and reaches the ground 2.5 seconds later. How high is the building? (g = 9.8 m/s2)
Initial velocity, u=0m/s
Acceleration due to gravity, g=9.8m/s2
Time taken to reach the ground, t=2.5 sec
Height, h =?
Using relation, s = ut + 
gt2
s = 0 * 2.5 + 
* 9.8 * 2.5 * 2.5
s = 0 + 4.9 * 2.5 * 2.5
s = 30.625m
39