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<p>Stephen Birkett wrote:
<blockquote TYPE=CITE>OK guys - time to get back to the classroom.....all
this levity will
<br>soon allow us to raise keys by mental thought alone.</blockquote>
<p><br>Grin... are you calling me "levitatious" ?? Why Stephen... and I
hardly know you !!
<blockquote TYPE=CITE>Ric B wrote:
<br>>I was kind of looking for a way of starting to plug in values easily
<br>>measured and looking at some things right away. But what you say
<br>>below would seem to make things a bit more difficult.
<p>Well, yes. It's always more difficult to measure dynamic parameters,
<br>especially with something like this for which it can't be estimated
<br>on paper. You really have to take some experimental approach to get
<br>anything but ballpark figures.</blockquote>
<p><br>As far as I can see Stephen, the only real problem here is to find
what I<sub>k</sub> is, and to do that we need to first be sure of what
you mean it to be. Specifically your notation leads one to easily think
of either the keys inertia in general or the keys inertia at the center
of mass.
<p>The center of mass r<sub>k</sub> having been now specified as a <<
distance from the fulcrum quantity >> presumably is not exactly stable
at one point throughout the whole key stroke.
<p>In either case I would guess that both the center of mass and the keys
inertia would change throughout a stable key stroke (stable velocity) in
a fashion somewhat more complicated then either a first or second degree
curve on a graph would represents. I'm just guessing here of course.
But maybe the shape of these two curves is something that should concern
us ??
<p>How to go about measureing both of these in an easy to accomplish fashion
tho I dont really know. And if a method easy enough to accomplish for the
average tech that at the same time can give a close enough approximation
does not exist... then what good is all this ?
<br>
<blockquote TYPE=CITE>The position of the centre of mass is needed, in
order to put some
<br>numbers into the analysis we've been considering.</blockquote>
Granted, but you just said that we could not use that at any given time
to find I<sub>k</sub> via M<sub> </sub>r<sub>k</sub><sup>2</sup>,
or did I misunderstand you ?
<blockquote TYPE=CITE>
<br>Stephen
<br>--</blockquote>
--
<br>Richard Brekne
<br>RPT, N.P.T.F.
<br>UiB, Bergen, Norway
<br><A HREF="mailto:rbrekne@broadpark.no">mailto:rbrekne@broadpark.no</A>
<br><A HREF="http://home.broadpark.no/~rbrekne/ricmain.html">http://home.broadpark.no/~rbrekne/ricmain.html</A>
<br><A HREF="http://www.hf.uib.no/grieg/personer/cv_RB.html">http://www.hf.uib.no/grieg/personer/cv_RB.html</A>
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