Superlesson
Project 9-2
Algebra
Chapter 9
Quadratic Functions and Equations
How can the graph of a quadratic equation help us to answer questions about the height of an object? Let's continue to investigate!
Part A, Quadratic Functions and Equations
1. Look again at the Galileo's Experiments Web site.
a. The expression d ~ t2 means d is proportional to t2. Suppose the ratio d divided by t2 is equal to 5. Write the equation for d in terms of t.
b. Graph the equation.
c. Where does the graph cross the x-axis?
2. Suppose the height of a golf ball is described after initial velocity from the ground of 4.9 m/sec.
a. Write the equation for describing the height of the ball after t seconds have elapsed.
b. By graphing, predict how long it will be before the ball returns to the ground?
Part B, Solving Using Tables and Factoring
3. Solve your equation from 2a by factoring.
a. Why does it make sense to have time equal to 0?
b. When does the golf ball reach its highest point?
c. How high will the golf ball be at that time?
d. Would you want to play golf on the same team with this person? Explain.
Part C, Making Connections
4. Name three methods you can use to solve quadratic equations.
5. Describe the limitations of each of these methods.