Re: [Phys-l] resonance animation

[Bernard Cleyet <bernardcleyet@redshift.com>]

Yes, that Wiki. page is very good.

 Swinging clocks are only for the curious and monied.  I wanted one  
'till I found the Super-mini Taktell **  would drive a pendulum  
well.  My ultimate will be an electro-magnetically driven pendulum  
with an optical encoder for its suspension.  For now I'm satisfied w/  
the encoder as the suspension of the "swinging" pendulum only.

I have a cheap (BOTH senses!) quartz fork pocket watch which I must  
reset several times a week, while my almost railroad (three position  
instead of five) watch, I let run down oftener than I need reset.   
(~once a week) However, it cost $235 to have adjusted.   My watch  
book gives its wholesale value at about $250,  but its a beautiful  
Hamilton.


**  https://www.ymonline.com/index.cfm? 
fuseaction=product.display&Product_ID=1104


> It could be
> stimulated to continuous revolution by modulating the drive frequency
> appropriately - a fine example of the pendulum's period variability  
> with
> amplitude variation.

Yes, B & B discuss this in pendulums less simple.

bc wants the double pendulum Lagrangian modified for his metronome  
driven double pendulum, so he can numerically model it.


On 2009, Jun 03, , at 16:09, Brian Whatcott wrote:

> Bernard,
>
> I set out to refresh myself by looking over the pendulum paragraphs in
> an old Starling & Woodall's Physics.
>
> (this is a book of which a reader might say, "if it ain't there, it
> ain't physics")  I was shocked to see how much more lucidly an  
> entry in
> Wikipedia read,  in this case:
>
> <http://en.wikipedia.org/wiki/Pendulum>
>
> To read it is to understand exactly what Captain Kater had in mind  
> with
> his reversible pendulum, and how Bessell made superfluous the careful
> equation of periods with a standard to one sweep in 24 hours or  
> better,
> by means of correcting results from a fixed reversible pendulum.
>
> This is to share with you that I do not dismiss the pendulum lightly.
> But consider this.
>
> A few months ago I bought a new wrist watch for about $5.
> It was a quartz movement in a thick stainless case, rather like the
> Submariner and similar Perpetual time pieces which still cost up to a
> thousand times as much.
> It was easy to see that this watch held time better than such an
> excellent mechanical movement.
>  Accordingly, I DO dismiss the pendulum movement as superseded, though
> it may well serve an ornamental purpose. You will agree I know,  
> that any
> compound pendulum clock for which the prime mover is both  
> mechanical AND
> part of the pendular mass, has its problems.
> Finally, I mention that I was taken with the animated diagram of this
> parametric pumping of the censer offered in this thread. It could be
> stimulated to continuous revolution by modulating the drive frequency
> appropriately - a fine example of the pendulum's period variability  
> with
> amplitude variation.
>
> Brian W
> p.s. For others who found your URL was broken, I repeat it here in  
> tiny
> format.
> <http://tinyurl.com/8o24k6>
>  One temperature compensation was the opposing iron/brass form.  
> Both of
> these rods tend to oxidize with time unless plated, unlike the usual
> quartz counterpart.
> **
> Brian W
>
> Bernard Cleyet wrote:
> > Brian!
cut