Hi can you please help me with this question. A golf ball is hit from the top of a tee. The quadratic equation y=-5x^2 + 20x + 0.05 describes its height,y, in metres as time,x, in seconds passes. Determine how long the ball is in the air. Thanks for the help
Since time is x, the ball will be on the ground when y, or height = 0
Therefore, all you need to do is solve the quadratic.
Using the quadratic equation formula, we get 2 solutions, as expected. They are: - .0025 and 4.0025 seconds.
Obviously, time, in this case, CANNOT be < 0 (negative), so time the ball was in the air is the LATTER.