Acceleration of Gravity

Purpose/Intro: The purpose of this lab was to determine the acceleration of gravity for a falling object, and also to use the computer as a data collector in order to gain experience.In this experiment, we used the computer as a data collector to collect some position (x) vs. time (t) for a rubber ball that we threw into the air.  Previous knowledge told us that velocity of an object is equal to the slope of the x vs. t curve. Therefore, we changed the graph to v vs. t (which calculates the slope of x vs. t) and graphed the slope. We used both graphs (x vs. t and v vs. t) to determine the acceleration of gravity of the ball.

After we tested the experiment multiple times, we calculated percentage error of each trial, which is equal to

We found that the velocity of falling object has a slope of 4.9 and therefore, the acceleration ( the derivative of the velocity) is 9.8. The graph of the position graph should be a parabola because the ball goes away from the motion detector (+ slope of parabola), reaches its vertex (zero slope), and then come back down toward the motion detector(- slope). Also, the slope of the graph is negative, therefore, the ball is falling or is in free fall.

This graph shows the position vs. time graph. The slope of of this graph is the velocity of the falling object.

This graph is velocity vs. time graph. The slope of this line is the acceleration of the falling object, consequently, the acceleration of gravity.

Data:

                               
Conclusion: In the end, we did accomplish our purposes by determining the acceleration of gravity. Also, we did practice using the computer as a data collector. Therefore, the purposes were accomplished. Also, we realized that we received different percentage errors for the different trials. One of the reasons why the experiment had errors is because there were multiple “throwers.” This could have affected the path the ball could have taken. Also, we believe the hand that threw the ball was recorded with the motion detector. Finally, we believe that air resistance could have been a source of error because the height the ball was thrown could have received more air resistance as opposed to a ball thrown at a shorter height.