Lab: Pendulum Investigation
Lab Partners: Mikey Haydt, Dakota Smith, and Bruce Herman
Date: 19 December 2014
Lab Partners: Mikey Haydt, Dakota Smith, and Bruce Herman
Date: 19 December 2014
Experiment
In this experiment, my partners and I each investigated the effects of changing a specific variable, mine being radius, while we kept the other variables constant [velocity & mass remained constant for me]. After taking the measurements, we each found our own respective %-difference and used compared the measurements we found using the devices to those found by the equations.
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Theory
Using different devices, we are to determine the accuracy and using a different variable to change by comparing the experimental value to those found using equations based on the variables we used.
Experimental Technique
Hooking up the equipment (force & rotary motion sensor) using a constant mass, I began the experiment. Given my variable to be radius, I kept the other variables the same. For me, mass = 120 g (0.12 kg), and velocity around 1.1-1.2 m/s (this is due the measurement of force being measured at intervals, where the intervals are not exactly the same). The different results of the experiment can be seen to the right.
Values for r are in cm, changed to m for equation |
Now having the different experimental results, I had to now use the original known variables to find the measured results [equations used seen at top of page]. Setting up a FBD, I went through multiple steps to set up an equation to find force for the different radii.
And finally, when placing these values into the %-difference equation [(2|exp - meas|)/ (exp + meas)], we get the following results for accuracy:
r = 0.43 m %-Diff = 5%
r = 0.435 m %-Diff = 11%
r = 0.44 m %-Diff = 0%
r = 0.445 m %-Diff = 3%
r = 0.45 m %-Diff = 8%
r = 0.455 m %-Diff = 13%
r = 0.46 m %-Diff = 6%
r = 0.465 m %-Diff = 6%
r = 0.47 m %-Diff = 10%
r = 0.48 m %-Diff = 19%
r = 0.43 m %-Diff = 5%
r = 0.435 m %-Diff = 11%
r = 0.44 m %-Diff = 0%
r = 0.445 m %-Diff = 3%
r = 0.45 m %-Diff = 8%
r = 0.455 m %-Diff = 13%
r = 0.46 m %-Diff = 6%
r = 0.465 m %-Diff = 6%
r = 0.47 m %-Diff = 10%
r = 0.48 m %-Diff = 19%
Analysis
Seeing as the accuracy was more-or-less spot on, the experiment was completed without any notable problems. The last measurement, which was conducted first, may has the least accurate result due to a small error in the alignment for the weight, due to the center of gravity possibly being off-centered. Altogether, the measured result is pretty on-par with the experimental result. The small inaccuracies could be from the inclusion of factors such as friction and wind resistance not being included in the actual measured results.
Conclusion
During this experiment, our group was to investigate the relation of the different variables along with the constants. To do this, we measured different variables using sensors and comparing them to computed answers. Altogether, the experiment was a success, and we were able to get clean, accurate results.