CBL
Lab 3

Determining the Acceleration of Gravity with a Bouncing Ball

Nov 4, 1995

Equipment: TI-82, racquetball, motion detector, CBL, 8-pin-DIN-motion detector
                 adaptor

IMPORTANT NOTE: this experiment will wipe out lists L1 through L4; if you need the data presently in there, save it elsewhere now!

1) Connect the TI to the CBL with the link (make sure that connection is secure).

2) Connect the motion detector to the SONIC port on the left side of the CBL, using
using the 8-pin DIN motion detector cable.

3) Use the AC power adapter for the CBL, since the motion detector-CBL
combination eats batteries.

4) Turn on both TI calculator and CBL.

5) Access and run Program BALL.... (Press ENTER until screen says "HOLD BALL
ABOUT 1/2 METER UNDER DETECTOR")

6) Hold the detector at a height of about 2 meters above a hard level floor.

7) Have someone else hold the ball right below the detector above the floor.

8) Press Enter on the calculator (the motion detector should start ticking) and then release the 
ball ... the CBL should record data for 4 seconds; the height above the floor (in meters) is stored in L2 and the time (in seconds is stored in L1; a graph of the height versus time will appear on the calculator screen, but not in real time.

9) The class can be divided into groups, with different groups analyzing different parabolas of the same bounce...share the data lists L1 and L2, and the program CHOOSE with everyone in the class.

10) Access and run the program CHOOSE to select a region of the data to analyze; choose only one complete parabola; the CHOOSE program moves the (time, height) data to lists L3, L4.

11) Fit the data with a quadratic fit: select STAT; select CALC; select QuadReg L3, L4; gravitational acceleration will be twice the a-value of the fit

12) Each group can determine the maximum height of their parabola (by curve fitting; then max height = -b/2a)

13) Then create two lists of data:

a) bounce number
b) max height for that bounce

14) The max data height as bounce should be fit by an exponential.

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