Quadratic functions appear in many situations in ordinary life. For this activity, you will gather some data on how a pendulum's length affects how long it takes to do its swing thing.
Get a piece of string about 6 or 7 feet long. Tie a weight on one end. Time the period for pendulums of at least 8 different lengths ranging from 6 inches to 5 or 6 feet. You may find it easier to time 10 swings of your pendulum and divide by 10 to determine the period.
As you record your data, enter it into your graphing calculator. Enter your times (in seconds) into L1 and your lengths (in inches) into L2. When you have entered all your data, determine the best fit quadratic equation:
y = ax2 + bx + c
Write up your data, your graph, and your best-fit function neatly on a separate sheet of paper.