The formula s= ut + 1/2gt^2
Represents the total distance "s" travelled by an object in time "t" which has an initial speed of "u" and is accelerating at the uniform rate of "g". It is customary to use the symbol "g" for acceleration due to gravity. However this equation is valid for any value of uniform acceleration.
We can derive the equation as follows.
The total distance travelled by a uniformly accelerating object is equal to average speed multiplied by time
That is: s = (average speed)*t ... (1)
And, average speed = (initial speed + final speed at the end of period t)/2
And final speed = u + gt
Therefore: Average speed = (u + u + gt) = 2u + gt
Substituting this value of average speed in equation (1) we get:
s = (2u + gt)/2]*t = ut +1/2gt^2
hope it helps...!!!