RMPh22 — rotating reference frame

The organisers' program records a 1 s, 240 fps video of a bead launched in a rotating frame, which you then measure in Tracker. Here the video and the tracking are in one place.

password
experiment
tracking
The paper calls the clip 1 s at 240 fps. The original program samples linspace(0, 1, 240), so its 240 frames span 0 to 1 s inclusive and the step is 1/239 s. Entering 239 here gives the timebase the frames were actually made on; 240 costs about 0.4 % on anything you get from a rate.
The length scale of the video is not given; set this once you have worked it out, or leave it at 1 and record raw units.
The bead is drawn the size the original draws it, which is 0.56 % of the frame — hard to see, which is why the exam has you autotrack it. These two aids only change the display.
Enter the password to begin.