Experiment 2
Acceleration due to Gravity
by
Eugenio Panero
PHY 2091-06
experiment performed: Oct 11, 2006
report submitted: Oct 18, 2006
Lab Partner:
Dominic Lombardi
Instructor:
Klaus Dehmelt
Introduction
The purpose of this experiment is to determine the value of acceleration due to
gravity.
Data
(See attached pages)
Data Analysis
Given the data, a graph of velocity vs. time can be obtained. The slope of the best
fit line represents the difference in velocity, that is, acceleration. The data points
represent velocity at a given time, and their value is calculated according to the
following formula.
where t is instantaneous time, and x is position.
Experimental Acceleration due to Gravity
450
Velocity / cm sec-1
400
350
300
250
200
150
100
50
0
0.00
0.05
0.10
0.15
0.20
0.25
0.30
0.35
0.40
Time / sec
The best fit line is the best representation for experimental acceleration. Its slope
is the experimental value, and the standard deviation of data points from it
represents experimental error. Therefore, the results for this experiment are:
Given a theoretical value for acceleration due to gravity of 9.792 m sec-1, then the
percent error for this experiment is given by the following formula.
Discussion
This experiment was overall successful. The precision of the graph, represented
by the standard deviation of the slope, is small enough to include reasonable
values for . The final percent error was within the limits of experimental error.
Nevertheless, several sources of error might have affected the outcome of the
experiment. The precision of the measuring tool for position offset was ± 0.1 cm.
However, imprecision would lead to a systematic measuring error. Since absolute
positions are irrelevant to this experiment, compared to relative position, given a
consistent error, the final result would still be largely unaffected.
Finally, the experimental method was rudimental in nature. The spark tape did
not homogeneously slide through the spark generator, which may have resulted
in slightly misrepresented offsets. However, given the low precision of the
measuring tools, this random error in nature is largely unidentifiable.
Conclusion
The experiment was carried out successfully, and yielded positive outcomes,
resulting in a sound approximation for acceleration due to gravity. The difference
between the given and the experimental value was within experimental limits.