The purpose of our lab was to find relationship between air resistance force and speed. We will find the relationship by dropping coffee filters. By graphing the data we collect we can use it to find a power fit for the air resistance formula F-resistance = kv^n. After we graphed our data and found the values for k and n, we used Excel to compare our experimental graphs to our modeled graphs.
Data Collection
For this experiment, we used a camera to capture the motion of the coffee filters as they fell a one story inside the design technology building. We started off with only one filter and repeated this five times. For each trial one filter was added until we had a total of five filters. We also used a two meter stick as a reference so logger pro could estimate the total distance the filter had fallen. After setting the reference, we could then determine the terminal velocity for each of the trials
The video above shows a similar example of the procedure performed to recorded the position of the coffee filters.
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In this picture we show the terminal velocity for each trial starting with one filter on the bottom left and continuing clockwise. As you can see, our terminal velocity for each trial is increasing as the mass of filters increases thus proving that the upward force on the filters is being overcome by the added mass.
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Here is a graph of the force versus velocity which yielded us with
a k value of 0.0055 and n value of 1.9247.
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With our experimental data now collected, we used the k and n values to make a model of a falling filter with air resistance by using Excel and using a time interval of 1/30 of a second.
Conclusion
Our data is only as good as our equipment and using an outdated camera that can not record very clearly is not a good start. The data is decent for all the graphs and are very similar when comparing their slopes. Overall I think the experiment went great even though we were not able to replicate our models to look similar to the data we recorded.
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