Acceleration of Gravity

Introduction:
In this lab we determined the acceleration of gravity on a freely falling object using Logger pro, a motion detector, rubber ball, and wire basket. As the ball is tossed into the air, the motion detector records the data on the graphing software.

Procedure:
1.)    Set up the logger pro program on the computer to graph the free falling object. After loading the position vs. time graph we had to verify that the vertical axis (position axis) was set from 0 to 4 meters and the horizontal axis (time axis) from 0 to 4 seconds. These values could be modified in order to get a more detailed graph if necessary. The motion detector was placed on the floor under the wire basket for protection from the ball.

2.)    Test the motion detector to make sure its collecting the desired data.

3.)    From about 1 meter above the motion detector give the ball a gentle toss straight up. The ball should travel directly above the detector for clear readings. Make sure hands are out of the way so they wont interfere with the data.

4.) Once the graph is on the computer, select the interval with the parabolic portion of the graph. Curve fit the graph and choose the quadratic fit for the graph. This will give the graph a negative slope because after the ball reaches its highest point it then accelerates in a negative direction along the y-axis.



Data:
*5 trials with the average and percent difference

Trial 1

The slope of the velocity vs time graph is 9.885 m/s^2 ; making the percent error 0.87%.

Trial 2

The slope of the velocity vs time graph is 9.449 m/s^2 ; making the percent error -3.58%.

Trial 3

The slope of the velocity vs time graph is 9.886 m/s^2 ; making the percent error 0.877%

Trial 4

The slope of the velocity vs time graph is 9.306 m/s^2 ; making the percent error -5.04%

Trial 5

The slope of the velocity vs time graph is 9.892 m/s^2 ; making the percent error 0.94%

The table shows the acceleration of both the position and velocity vs time graph along with the percent error. The bottom portion shows the averages of each column.

Conclusion:
This lab gave us the clear understanding of the freely falling object. After graphing the path of the tossed ball we were able to gather the slope of the ball's path. Most of our trials were in the actual range of gravity's force with an average of -1.2% percent error. There was two trials where the percent error was much higher but it could have been due to the motion detector gathering some one elses hand movents after the ball was released.