Ken's Inertia

[Yardbird47@aol.com]

Ken Sloane rote:
<< the relatively slow movement of the hammer might be hampered by the static
friction in the note more than when moving it quickly.>>
The point here which could be answered by someone at an engineering school is
whether the two coefficients (static and dynamic) are separated by a discrete
but sharp step or whether in fact there is a grey area in which the levels
are joined by a slight curve. I know there's such a thing as low-temperature
physics. (My cousin works at Livermore, doing research at close to 0 degrees
K). the answers we need might be found in a branch called "low-velocity
mechanics".
Paradoxically, Ken, there may be a phenomenon quite to the contrary. Remember
that the force of friction is the product of the appropriate coefficient and
the force pressing the two together. Once again this is where inertia comes
in. Key in mind that the motion is our three levers starts with the bottom
one, the key. As it punches upwards, it must overcome the inertia of the
upper two. When all three move in unison (pun intended), inertia is overcome.
Until that point any disparities in speed (and the resulting acceleration)
will show up in relative terms as a lower lever which is moving pressing on
an upper level which is stationary (with respect to the former). This
pressure is above and beyond the usual force of gravity on these parts, and
adds its own measure of friction on top of gravity's.
Brief and subtle though it may be, a high-inertia action (regardless of its
downweight or balance weights) will inherently have higher friction during
the opening moments when inertia is being overcome.
Then again, there's the other source of inertia, at the high-pressure spot in
the leverage, where the knuckle's vectors of motion are changing from sliding
to lifting.

Ken Sloane rote:
<<Also, I have a gut feeling that the acceleration of the hammer would occur
over a small period of its movement (with slow movement of the hammer) and
that acceleration would more likely occur over a greater period of movement
with faster hammer movement.>>
This is right in harmony with the effects of inertia. The more acceleration
you ask of a heavy body, the slower it will be to comply. Seemingly the only
thing which would shorten the compliance time would be more force. But then,
unless you the pianist had measured your attack on such a key in such an
action. this extra force intended for the initial push would still be there
pushing, long after he parts were rolling, and in continuing to push,
supplying overflow amounts of momentum to the hammer

Maybe we should be trying to solve these mysteries with a transcendental
meditation approach.....;-)

Bill Ballard RPT     "I gotta go ta woik...."
NH Chapter         Ian Shoales, Duck's Breath M. Theater