On Tue, 17 Aug 2010 19:32:43 -0700, John Larkin
wrote:

On Mon, 16 Aug 2010 18:32:25 -0500, John Fields
wrote:

On Fri, 13 Aug 2010 16:16:39 -0700, John Larkin
wrote:

On Fri, 13 Aug 2010 17:20:27 -0500, John Fields
wrote:

On Fri, 13 Aug 2010 09:07:44 -0500, John Fields
wrote:

On Mon, 09 Aug 2010 16:37:19 -0500, John Fields
wrote:

From the schematic:

1. Set the DSO for a single sweep triggered by channel 1 going high.

2. Pull M1 away from M2 and M3, which are just barely touching,
and let them settle for a few seconds.

3. Arm the DSO.

4. Release M1 so that it hits M2 directly across from where M3 is
touching M2.

5. Read the time it took for channel 2 to go low after channel 1 went
high. That'll be the time it took for the momentum accumulated by
M1 to be transferred to M3.

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"Slow", "Medium", and "Fast" refer to the pulse width of the pulse on
channel 1, the width of which was determined by releasing the ball
farther and farther from plumb.

the fact that there _is_ a trailing edge means that M2 wasn't hit
squarely or that there are imperfections in the rig.

In either case, the bounce represents an impedance mismatch reflecting
power back from the load to the source.

In any case, the momentum transfer time is from the leading edge of
the trace on channel 1 to the falling edge of the trace on channel 2.

I'll get some more data together as time permits, and post it, and the
video's in the works...

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New game:

30.jpg is with M3 tied back, M1 pulled about 30° away from plumb when
released, and shows how long it takes for the momentum in M1 to be
transferred to M2 and have M2 lose contact with M1; just about 100µs.

Did I guess good or what?

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Not really.

In the 3 ball case, which is what was presented originally, you
guessed 100µs from the make of M1 to M2, to the break of M3 from M2,
which is really about 150µs, a 50% error.

Since I hadn't suggested a 2 ball reaction when you made your guess
it, of course, (the 2 ball reaction) didn't apply, so what you _must_
have been referring to was the 3 ball case, where 100µs doesn't work.

But, more importantly, and I don't know whether you remember or not, a
few years ago (maybe six or seven) a question came up about marbles
being run down a tube, hitting other marbles, and how long it would
take for the hit marble to move away from the hitter.

Your take on it was that the hit marble would move away from the
hitter as soon as the shock wave from the hit traversed the hit
marble, and I built my Newton's cradle to test your hypothesis.

As it turns out, you were wrong, and it takes much longer for the mass
to move than you predicted.


What bull. I was pretty close for things like this.

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"For things like this"???

That's just another catch phrase designed to minimize the significance
of your error, charlatan.
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Your various measurements pretty nicely straddle my estimate.

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They don't straddle your guess, since your guess starts at zero and my
numbers are all longer than your guess.

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JF