Adjusting wippen assist springs

[Sarah Fox]

Hi Ric,

But wait!  Before we jump into the empirical we're almost "there" with the
theoretical!  Pop an aspirin and humor me for a sec...

You wrote:

> AhHaahah... :)... Sarah... granted that gravitational acceleration on the
key is
> nothing compared to the resistance against the finger too accelerating the
key
> faster then gravity itself would do... but once done, that inertia doesnt
simply
> dissapear into blue heaven. Nor does it simply get burried in the key bed.
It
> applies its force against whatever is resisting... and that includes the
stuff
> sittting on the capstan.

Ah, but inertia is inertia.  It doesn't go anywhere.

I think you're saying that the energy transferred from the finger to the
keystick gets transferred to the capstan.  That's true.  However, not *all*
of it get transferred.  Consider yet another illustration:

You're sitting on the hood of a car.  The car runs into a massive concrete
barrier at 5 MPH.  You fly off of the hood, over the barrier, and head-first
into another barrier.  Now repeat the experiment with a freight train.  Same
speed -- 5 MPH.  We'll assume we can build a barrier to stop even this
massive machine dead in its tracks.  You fly off the top of the freight
train into a barrier.  Q: Which is worse?  A:  Neither.  They're both
exactly the same to you.  You still collide with the second barrier at 5
MPH, with the same kinetic energy -- your body mass, times your velocity
squared.  The inertia of the car vs. the freight train has nothing to do
with the severity of your impact.  Likewise, the kinetic energy of the car
vs. the freight train has nothing to do with your impact.

Where does all the kinetic energy of the freight train go?  Experiment 2:
Repeat experiment 1, except insert a Volkswagon inbetween the car/freight
train and the first barrier.  I submit that when struck by the car, the
Volkswagon will still be recognizable, albeit banged up.  When struck by the
train, it will be foil.  This still doesn't affect you.  You still fly into
the next barrier at 5 MPH.

The moral of this little thought experiment is that it is the velocity of
the key, not the inertia, that affects how fast the wippen moves.

Now with experiment 3, I'll push the car up to a speed of 5 MPH before it
crashes into the barrier.  Then I'll push the freight train up to that
speed.  Hmmmm....  On second thought, I think you would probably prefer
sitting on the freight train, 'cuz I'm not going to get that thing moving at
all!  Even if everything were completely frictionless (e.g. in
microgravity), it would take a lot of time, effort, and distance for me to
get that thing moving at 5 MPH!

> While your 1 kg is  perhaps illustrative, I suspect that the mass levels
we are
> dealing with combined with accelleration levels possible alter the picture
you
> are trying to draw here. Compounded by the fact that in your example the
inertia
> levels in the key are many times that of the "top action" which is the
reverse
> of what we are dealing with. In anycase... you've gone and given me one of
my
> headaches... hehe..

Sorry for the headache!

Even though my examples are extreme, they illustrate physical truths.  While
these effects may vary in degree, they do not occur in one situation and not
in another.  The kinetic energy of the keystick at the time of its bottoming
is ALL LOST.  For a given velocity of keystick, higher inertia means more
wasted energy.  That's really the bottom line.

> But I'm willing to be convinced I'm wrong here.

YOU'RE WRONG!!  :-P~~~~~~

> Tell you what... this is
> measureable actually. Take an action model set up so it can be run both
ways.
> Contrive some way of measureing the output force... how high  the hammer
will
> throw a 50 gram weight for example... or get really fancy measurement
> equipment... then exert a 5 kg force downwards and measure the difference.
>
> If you are correct, then the set up with the whippen assist spring will
throw
> that 50 gram weight higher.  But this is the opposite of my present
> understanding.

I'll probably do some sort of analysis in my abundant free time -- for other
reasons.  Not anytime soon, though.

Peace,
Sarah