Linear velocity laboratory LRC start

Last term a RipStik run suggested that starting on the small slope at the LRC balanced against the force of friction on the RipStik. This term the ball rolls were started at that location.

The slow speed rolls were still done on 1.5 meter intervals. Medium speed rolls were timed across 3 meter intervals. Fast rolls were done on six meter intervals.

0 meters was off of the first post. Thirty meters was in front of of the south faculty building.

The only downside to this arrangement was that this puts the bowler in the January morning sun at 8:00. Hot, sweaty mess.
Full sun at the 0 meter mark.


Preliminary results suggest this countered friction, especially where friction had the most impact at low speeds.


The speeds came out similar to those in the past. The new launch location is more exposed to crosswinds, but that was not an issue this term.


Prior to going out on the sidewalk, the students were asked to predict what a time versus distance graph would look like for this data. The class has a strong mathematical background. Two time versus distance graphs were already done earlier this week. A RipStik time versus distance on Monday and a walking time versus distance on Wednesday. In theory, given their mathematical background and the two prior days of experience, the students might be expected to correctly extrapolate to the three speed system.


While a couple of students did obtain a correct extrapolation, the majority did not. Some students left their sheet blank, unable to come up with any prediction.


One student orally predicted that the data points would get closer together. That the data points may get further apart or closer together is a relatively common misconception. 


Board notes after the data gathering. 


One student was able to copy and paste data on their Android phone from their stopwatch app to their Keep notepad.


Data provided by a student was reflected onto the Smartboard. The Smartboard mirror app was used to demonstrate how to put the report together. 

This term, with the larger sidewalk chalk supply running low, a smaller sidewalk chalk was tested. Roughly one stick of chalk was used per run.

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