Chris,
Refering to earlier.
> May I suggest an experiment for the proponents of the ball?  Operate =
with as=20
> little damping as possible and compare to a true sine wave equally =
damped.

     It may be easier to just measure 1) the period and 2) the damping=20
factor. The damping gives an exponential fall off in the amplitude of =
the=20
oscillation. These should be easy to do using your A/D logging program.=20

I wasn't thinking of just period and damping.  My thought was that if =
the pivot axis is changing toward a more stable configuration (different =
sized ball pivots or no upper ball) the pure sine wave will be deformed =
by a higher restoring force with an increase in displacement and provide =
experimental evidence for ball pivots being more stable at least in the =
extreme.

Randy.










Chris,
Refering to earlier.
>=20
May I=20
suggest an experiment for the proponents of the ball?  Operate with =
as=20

> little damping as possible and compare to a true sine wave =
equally=20
damped.

     It may be easier to just measure =
1) the=20
period and 2) the damping 
factor. The damping gives an exponential =
fall off=20
in the amplitude of the 
oscillation. These should be easy to do =
using your=20
A/D logging program. 
 

I wasn't thinking of just period and =
damping. =20
My thought was that if the pivot axis is changing toward a more stable=20
configuration (different sized ball pivots or no upper ball) the pure =
sine wave=20
will be deformed by a higher restoring force with an increase in=20
displacement and provide experimental evidence for ball pivots being =
more stable=20
at least in the extreme.
 
Randy.