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Re: [Phys-L] fidget spinner: more data, more analysis, timestamps, force-law plot




On 2017/Sep/21, at 10:30, John Denker via Phys-l <phys-l@mail.phys-l.org> wrote:


BC spinner #1 has a loose bearing. This is observed explicitly,
and also implicitly at the high-speed end of the recorded data,
where the data is very messy, which can be explained by wobble
and shimmy. Furthermore, over most of the range the friction
is dominated by a zeroth-order term, more-or-less in accordance
with Coulomb's law of sliding friction


All of them (my four) wiggle.

Evidently I haven’t posted my graphs. IIRC, (I’m 80 and was concussed by a mugger), My conclusion is mostly lin. and quad. not much da Vinci dissipation.


https://phys.org/news/2016-05-leonardo-da-vincithe-systematic-friction.html