1) A baseball is hit from a height of 0.8m. After t seconds. its height h, in metres is measured by h = -5t^2 + 20t + 0.8
a) use the method of completing the square to find the maximum height of the ball?
b) How long is the ball in the air?
This shows how to use completing the square to find maximum height, and how to calculate how long a ball is in the air.