Class Copy

# TI-83 with the Pendulum Lab

## Graphing the Pendulum Period

- Clear any equations in the equation editor: Y= . Delete each function using the arrow keys and DEL .
- Clear the statistics lists: 2ND + 4 ENTER
- Enter the string length (in meters) data as L
_{1}: STAT 1 . - Enter the period (secs) data as L
_{2}. A set of sample data is shown to the right. -
Select a statistics scatter plot: 2ND Y= 1 .
- Press ENTER when the cursor is highlighting "On".
- Use the arrow keys to select the Type: scatter graph.
- XList:L
_{1}and YList:L_{2}should select automagically. - If not, use the arrow keys and ALPHA 1 and 2 to select L
_{1}and L_{2}. - A properly configured screen shot is at the right.

- Set the optimum stat plot graphing window: ZOOM 9 .
- The data should be displayed. The user can use TRACE to examine data points.

## Modeling the Length / Period Relationship

The TI-83 can find a mathematical equation that models the pendulum system data you have gathered.

- Turn on a useful diagnostic: 2ND 0
*X*^{-1}. - Use the arrow key to scroll down to DiagnosticOn. Press ENTER ENTER
- Enter the pendulum data as described above in steps 1 through 3.
- Press STAT and arrow right to CALC.
- Arrow down to option A: PwrReg. Press ENTER ENTER
- A typical equation display screen is shown at the right.
- The equation that best fits the set of sample data in this case is Y=2.22 X
^{.53} - The closer r is equal to 1 the better the equation 'fits' the data. The r=.99 shown here means the equation is a very good fit to the data.

## Graphing the Ideal Length / Period Relationship

It is interesting to compare the ideal mathematical model to the actual data. The ideal equation is Y=2 X^{.5}

- Enter the ideal equation into the equation editor. Y =
- Y
_{1}=2*X^.5 - Use GRAPH to view your data and the ideal equation.