Day 29: Results from Focus Group and Meter Stick Holder

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From yesterday's trial with Deepa, the team found several flaws with the current procedures. One very important find from the focus group is that the procedures do not specify which highlighted points are needed in order to find the drag coefficient from the graph. After Deepa completed all the drag coefficient procedures, she found that her value for drag coefficient was .05, however, the correct range should be around 1 to 0.4. Upon further analysis of her data and graphs, we found that moving the highlighted area to include points near t = 0 resulted in the correct value. After adjusting, Deepa's value for drag coefficient changed to 0.4. 

While Deepa was finishing the experiment, the team also began the rough design for the meter stick holder. The team decided that there should be a meter stick holder to simplify the procedure by eliminating a few lines from it such as making a person hold the meter stick upright. Furthermore, a meter stick holder will eliminate steps involving marking the tape on the floor and aligning everything up.

Figure 1: Meter Stick Version 1

As seen from the photo above, the meter stick will be fitted onto the stand. Protruding out left and right from the stand are the target marks. These marks are aligned to the center of the meter stick holder shaft, thus eliminating any confusion from students on where to mark the tape and where to drop the ball. The arrows that are on the front and back of the stand are there to stabilize the stand and also to help align the meter stick assembly with the phone/camera. Steps in the procedure will go as such: 
  1. Attach the meter stick to the meter stick stand.
  2. Align the meter stick stand (with the meter stick attached) so that the arrows are pointing directly at the camera.
  3. Drop the ball directly at the center of either targets. If the ball misses the target, delete the video and redo the trial. (A ball dropping outside of the target will skew results)

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