Acceleration day one and two

Ahead of class on Monday a 27 meter run was set up off of the LRC. 

A trial run was done. A flatness in velocity had been seen summer 2025 in the range around 9 to 15 meters. The trial featured swizzle start just past nine meters. This appears to have helped.

The Desmos file automatically calculates the intermark velocity from the first table. For this run the stopwatch was stopped at 27 meters. That timing may have been late. 

Prior to the in-class run, paper was distributed and students were asked to sketch the time versus distance graph for an object starting at 0 m/s and going faster and faster. The word acceleration was studiously avoided.

The graph at the upper left below preceded the distribution of the paper.

The chart at the lower left depicts the three sketch formats seen in class. A linear line was most favored, followed by the parabolic line. A couple of students opted for a convex curve that lost slope with increasing values of time. The right side was posted after the run.

The in-class run was, if anything, a smoother acceleration. For this run the 27th meter was marked as a lap. From 24 to 27 meters the board hit 2.988 m/s. At that speed things are happening fast, stability is decreasing. Shifting to stop takes extra brain processing time. Staying on lap timing decreases the mental load.

An acceleration of 0.16 m/s² was obtained. R² went from 0.9980 on the pre-class run to 0.9991 on the in-class run. That is a remarkable fit, and a steady acceleration.

Wednesday the decelerating run was done as in prior terms. The only change was the westward shift of the zero line due to the new marks being based off of the LRC post. Had the tape measure and chalk been taken to class, the new parking lot entrance might have been attempted this term. 

The data could be better modelled by some sort of bilinear model, but data is as data does. 

The initial velocity was perhaps a tad low, which put 10.5 meters out of reach.