1. When h = height (ft) and t = time (sec), the quadratic equation h = 20t-5t can be used to determine the height of a football after it was kicked up into the air with a speed of 20 ft/sec.
a.
How long does it take the football to hit the ground? How can you tell?
b.
What is the highest point reached during the flight of the ball? How can you tell?
C.
When was the ball exactly 15 feet off the ground? How do you know?