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 >
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