11-30-2020, 07:27 PM
(11-30-2020, 06:12 PM)Jens Noritzsch Wrote: The graph is for forced oscillation in order to record the pendulum response (amplitude) like in the video to the spring oscillator www.youtube.com/watch?v=VbL4IInVAO4, for instance.
The result tab shows the latest value provided by the autocorrelation. The algorithm is documented in the experiment info via three-vertical-dots menu – or the .phyphox source, of course…
Thank you so much for a prompt response. I'm sort of a physics enthusiast only so it is entirely likely I do not properly understand the experiment. I get the meaning of that 'resonance' graph for the driven pendulum case - I just wonder what it means for a non-driven case.
For a practical pendulum, non-driven, the amplitude gets smaller with time (due to damping), and the period of oscillation does get smaller with time as well (I suppose due to various friction/imperfection of a practical experiment?). Both the change of amplitude and the change of period gets smaller with time. Since 'resonance' graph plots normalized amplitude vs frequency one would expect that the resulting graph would show a decreasing amplitude as frequency increases - which my graph does indeed do that somewhat. But I do not understand why there is clump of data points at ~0.83Hz and another at ~0.8357Hz. What is so special about those particular frequencies?