[Phys-L] Spinner Decay Models - Aftermath.

[brian whatcott <betwys1@sbcglobal.net>]

The recent thread on spinner dynamics and decay time models provided two 
surprises.

1) In quite respectable papers, authors question the usual explanations 
of pendulum amplitude decay: See for example~

https://arxiv.org/ftp/physics/papers/0306/0306081.pdf

(I notice he cautions against piece-part analysis of such results, bc! )

https://www3.nd.edu/~bolster/Diogo_Bolster/Research_6_-_Vortex_Rings_files/21%20-%20Pendulum.pdf

(Vortex rings as a dissipation element in pendula!)

2)  I was surprised at the great variety of microprocessor based gadgets 
presently available. If one chooses an Arduino processor at  $10 to $30, 
running at 8MHz to 84MHz for example and adds a sensor from a long list, 
see for example,

https://www.adafruit.com/category/35

and an SD memory read write card, a custom datalogger that can provide a 
list of spinner periods resolved to  microsecond unit increments is 
within  reach at attractive cost and with easy access to C software 
libraries for driving the rig as needed.

 I cannot help but suppose that students who are exposed to such 
projects would be developing a valuable skill in the job market. Yes, 
and produce interesting Science Fair results for ARXIV too!


Brian W