Key Leads and Inertia

[David Love]

I'm not an engineer and will have to defer to those who can comment on this
in a more informed way, but your reference to the key doesn't change my
point.  Movement of the key is being resisted by a variety of factors the
would eliminate any significant effects of momentum in key travel, or so it
seems to me.  

David Love
davidlovepianos@earthlink.net


> [Original Message]
> From: Richard Brekne <Richard.Brekne@grieg.uib.no>
> To: Pianotech <pianotech@ptg.org>; <davidlovepianos@earthlink.net>
> Date: 5/1/2003 10:59:41 PM
> Subject: Re: Key Leads and Inertia
>
>
>
> David Love wrote:
>
> > It seems to me that because everything resists being moved (inertia)
that
> > acceleration probably takes place through the entire key stroke.  I
would
> > guess that the first mm of movement doesn't achieve much for the reasons
> > that have been  discussed, namely the flexing, compacting of various
parts.
> >
> > David Love
> > davidlovepianos@earthlink.net
> >
>
> We were talking about the acceleration of the key itself David, the
actions
> compliance as a whole is a seperate issue, albiet a good one. Of course
> acceleration / or deacceleration occurs through the whole key stroke,
(except
> perhaps very rarely... what a steady touch tho eh ?). But the presence of
> acceleration does not simply eliminate the affect of any momentum, and
that
> seems to be what is being said.
>
> The applet I sent a link clearly showed that all other things being
equal, a
> given mass halfway along the key would accelerate faster then half that
amount
> out at the end for the same downward force.
>
> I put 100 grams on the "rope" as it were, and 250 on the left side edge
of the
> "platform". Then ran the applet first with 250 grams at the right side
edge of
> the platform, and then 500 grams half way in on the right side. This
resulted in
> a faster acceleration for the 500 gram configuration. The 100 grams
pulling at
> the rope is the input force here, and the "platform" is the key. Only
> significant detail missing relative to the inertia question isolated from
all
> the other stuff thats being mixed in, is the orientation of gravity here,
as the
> "platform" rotates horizontaly. That however, just takes gravity out
(more or
> less) of the picture in the demonstration.
>
> Its all part of a link to an online physics resource. Good for clowns,
Steinway
> enthusiasts, and Wissner lovers everywhere :)
>
> Cheers
>
> RicB
>
> I'm off for a weekend of camping. See you all on monday !
>
> RicB
>
>
>
>
>
>
>
> --
> Richard Brekne
> RPT, N.P.T.F.
> UiB, Bergen, Norway
> mailto:rbrekne@broadpark.no
> http://home.broadpark.no/~rbrekne/ricmain.html
>