Drag Force on a Coffee Filter

Intro:     The purpose of this experiment was to study the relationship between air drag forces and the velocity of a falling body. What we did in this experiment was we started off with nine coffee filters. When we dropped the pack of nine filters over a motion detector, it registered how fast the pack got to the motion detector. After four or five trials, we subtracted a filter and did the four or five trials with the eight filters. We continued to subtract a filter after four or five trials until we had no more filters left. In the end, we analyzed our data and placed it into a graph. The data told us what the terminal speed relative to the number of filters and also, how close to the Power Law fit our numbers were.

Questions: Some questions that were incorporated into the procedure tested our analysis of the procedure.

1) What should the position vs. time graph look like? Explain.   

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  -      I thought the position vs. time graph should look like this because as time elapses, the filters   will get closer to the motion detector. 

2)    From the curve fitting and analysis graph, what should the slope represent? Explain

<!--[if !supportLists]-->-          <!--[endif]-->The slope should equal the terminal velocity of the falling coffee filters.

Results: 

The data table from all our trials. The average terminal velocity is shown on the right side.

This graph shows a representation of what the slope for on of the 8 filters experiment

Conclusion: The actual value of A*x^B is B should equal 2. Our value was 2.55. Therefore, our percentage error was 27.5%. This was a very large error and we contribute the "off-ness" to the shape of the filters. The instructions clearly said to keep the filters straight and we tried, but it was hard when we dropped the last filter more than 50 times. Also, we tried to get the best fit on the slope and the fit was sometimes off by a lot. In the end, I learned about mass and how it affects the velocity of a falling object and also how the air drag force is related to it.

The red points show our data while the solid line shows what the true value of A*x^B is equal to.