July commences with an onslaught of cloud blood.
Today we used Cabrillo's Tracker program to finish gathering the position vs. time data from each of the four videos (stationary, slides, dynamic, Rowgometer). The only problem seems to be that every three frames are the same; Tracker seems to calculate velocity - 1st derivative of position - merely as the slope between two successive position data points, so there are many near-zero values in the velocity data, and the acceleration is pretty wonky.
Ex. three successive position data points: 