Help for Exercises 72-75 on page 523
For Exercises 72-75, the given equation has a graph that is a downward facing parabola. The maximum height can
be found using the vertex formula. Remember that the vertex formula will yield the value of t (the independent
variable, time) for which the ball reaches its maximum height.
For Exercise 74, look at the symmetry of the parabola. The time it took for the ball to reach its maximum
height will equal the time it takes for the ball to travel from this height to the point where it lands on the other
side of the net.
For Exercise 75, refer to the photo. This offers a clear example of one way the path of the ball is affected.
There are other variables that can also alter the path of the ball.