045 Kinetics v=at d=½at² p=mv ½mv² mgh

This exercise began at 8:00 with the laying out of a 90 meters RipStik run for the statistics chapter 4.1 introduction to linear regression functions. This left behind the 3 meter marks needed for 045 at noon in physical science.

Friction would again plague this exercise. Perhaps WD40 in the wheel bearings would help. The wheels are not freely spinning.

I wisely prepositioned a kilogram scale in A101 which I used post hoc to add mass into the equations.


A trial line leveling was done off of the 18 meter mark. This produced only on the order of 0.46 meters of height. Yarn was suboptimal, but the yellow surveyors line went missing. 18 meters was chosen because 18 to 21 meters has a shallower slope, I was hoping the steeper slope would help, but the steeper slope did not.

The yarn was sufficient but suboptimal.

A trial height measurement ahead of class.

The gear needed to pull this off is plenty. Multiple timers cover for outliers and mistiming.

The Smartboard with the spreadsheet up and on display. All calculations were actually done on the whiteboard.

The three meter speed trap. 

The 18 meter run, trimmed from 21 meters last term.

The left board with for of the six equations.
a = constant, d=½at² , v=at, p=mv

Color codings were chosen on the fly. Numbers across the bottom are post hoc.

The right board. KE=½mv², GPE=mgh

Diagram detail. Numbers are post hoc.

The six equations.

The gist of the results. The loss in velocity was thirty to forty percent, well beyond what one would hope to obtain. A whopping 60% of the gravitational potential energy was lost. That did make the bottom turn nice and slow.

There was also a need to run more practice runs to get accustomed to the run. 

Resolving the losses that lessen the potential impact of this demonstration has to be a lead consideration in future runs of the demonstration.

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