Amusement Park Physics

Lincoln High teachers Jerel Welker and James Rynearson recently attended a conference in Anaheim preparing to take students to an amusement park with the primary purpose of collecting and analyzing acceleration data. Over the next few weeks, we will be working on web pages which show some of the data and the analysis which we were able to perform. Please check back again. For those of you who were on the trip with us and would like an early copy of the data, please email jwelker@lps.org

The software used is available as accel.83g. The file is a group of TI-83 files which will need to be unstuffed or unzipped. Send the entire group of files to a calculator using the Graph-Link. A description of each of the files is listed below.

Software Description:

CALIBRAT

The calibrat software is designed to calibrate the accelerometer. Run the program Calibrat. Select the appropriate channel (the 3-axis accelerometer will be calibrated 3 times). Select Channel 1. Position the accelerometer so that the arrow of the axis plugged into channel 1 pointing down. Press Enter to read the voltage. Enter -9.8 as the calibration value. Position the accelerometer with the arrow pointing up. Press Enter. Enter the calibration value as 9.8. This will calibrate the CBL so that a reading of 9.8 m/s^2 will result if the accelerometer is not accelerating. If you are using the 3-axis accelerometer, repeat the calibration for channels 2 and 3. Use the appropriate position for the axis which is plugged into each channel.

ACC3AXIS, ACC3TRIG, ACC1AXIS, ACC1TRIG

These four programs are essentially the same to use but each functions with a slightly different operation or method of data collection. The ACC3AXIS and ACC3TRIG are designed to be used with a triple axis accelerometer while ACC1AXIS and ACC1TRIG are designed to be used with a single a single axis accelerometer. The ACC3AXIS and ACC1AXIS are deisgned to begin collecting data when the [ENTER] button is pressed on the calculator. The ACC3TRIG and ACC1TRIG are designed for use when the CBL needs to be disconnected from the calculator before the data is collected. Sampling begins when the [TRIGGER] button is pressed on the CBL. To collect data:

1. Run the appropriate program for the equipment and setup of the activity.
2. Determine the number of data points and the time interval. Use a stopwatch to time the duration of the movement. Divide the total time by the desired number of points to find the time interval between data points. By trial and error, we have determined that a TI-83 with a triple axis accelerometer will only hold 300 data points due to memory constraints. The TI-83+ has no such limitation. The CBL is limited to 512 data points.
3. At the prompts, enter the number of data points and the time interval for collection.
4. When using the [TRIGGER] programs, a prompt will appear to enter the prestore data percentage. The CBL will record data prior to the actual triggering if you choose. This may be useful if you are not precisely sure when the motion will begin and want to have a baseline before the motion occurred. Enter the desired percent of points to be collected prior to the triggering. For example, if you are collecting 300 points at 0.1 seconds and a 10 percent prestore is entered, the CBL will record 30 points or (30 * 0.1) three seconds of data prior to the trigger and 270 points (270 * 0.1) or 27 seconds of data following the trigger.
5. Collect the data by pressing [ENTER] when prompted on the calculator or remove the link cord from the CBL and press [TRIGGER] on the CBL if a trigger program is being used.
6. The ACC1AXIS and ACC3AXIS will automatically get and graph the data from the CBL. When using ACC1TRIG and ACC3TRIG, the GETACC program must be ran to get the data off of the CBL. Even if the CBL shuts down, the data will be stored in the CBL unless it has been cleared by running another program or removing the batteries. Run GETACC and select 1 or 3 axis accelerometers at the prompt.
7. The single axis accelerometer data is stored with time (sec) in L1 and acceleration (m/s^2) in L2. Triple axis accelerometers store the time data in L1, Channel 1 data in L2, Channel 2 data in L3, and Channel 3 data in L4. The magnitude of the acceleration vector is calculated and stored in L5. The magnitude is the square root of the sum of the squares of the individual acceleration vectors (L2^2 + L3^2 + L4^2)^(1/2). The triple axis programs will graph time (sec) vs magnitude of the acceleration (m/s^2) stored in L5. Acceleration in any of the three planes may be shown by changing the Stat Plot to the appropriate list.

GETACC

GETACC is designed to download the data from the CBL after acceleration data has been collected. This program must be used after running one of the programs which collect data following the pressing of the trigger button on the CBL. Additionally, additional calculators may be connected and download the data following the use of the ACC1AXIS and ACC3AXIS programs.

The data will be downloaded and displayed as described in part 7 above.