Peak Acceleration In Your Stroke?

Patrick Johnson said:
I'm not interested in dueling dictionaries, so I'll just repeat my point:
The stick:

1. Accelerates up to (or maybe a little before) contact with the CB
2. Decelerates dramatically upon contact with the CB
3. Re-accelerates (but not fully) after the CB is gone.

This means there is no such thing as "accelerating through the CB" in the sense of a continuous, unbroken acceleration or, most importantly, in any sense that can directly affect CB action.

You'll have to email Bill Clinton to debate the definition of "from".

pj
chgo
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Especially when you have been shown to be incorrect...yet again.
(-:

Edit: But I'm in a charitable mood, so let me help ya out 'ol timer".

I summed up and agreed with your above laboriously reiterated explanation regarding the lack of acceleration through the ball when I wrote...much more succinctly than you.


"" So if "accelerate through the ball" is defined as continuous acceleration from before CB impact to after it...then no, that does not take place."

You see Patrick, "before CB impact" relates you your number 1 and "to after it" handles your #s 2 & 3.

This is yet another example of where you have taken comments people have already posted...rephrased them...and cite the same things as though you were teaching the prior poster some erudite lesson.

Then you wrote..."This means there is no such thing as "accelerating through the CB" in the sense of a continuous, unbroken acceleration or, most importantly, in any sense that can directly affect CB action."

But no one said there WAS such a thing as you just described! At least I certainly didn't.

I AGREED WITH YOU PATRICK....GET IT?????????????

I merely went on to suggest a prop bet which, if worded the way I worded it would be correct because the cue DOES accelerate through the space where the ball used to be FROM THE POINT IN TIME AFTER CONTACT.

You really seem to be slipping old boy. But there is medication.

Jim


But if "through the ball" is defined as from the instant of contact and afterward...which IMHO is a more precise definition of the phrase... then acceleration does occur
 
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you have been shown to be incorrect...yet again
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As I've said before, Jim, nobody but you much cares what the "score" is between us - least of all me. I restated my point because it got buried beneath your pile of pointless nitpicking, not to win some contest with you.

Stick to pool.

pj
chgo
 
Study the acceleration trace.
 

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JohnnyP said:
Study the acceleration trace.
Click to expand...
The acceleration of the stick is expected to have a large negative peak at the instant it hits the cue ball, but that is not evident on the red trace. Either it was too brief to be captured, or it was so large it overloaded the recording system. The re-acceleration does seem to be visible as a positive peak in the red trace after tip-ball impact. It is expected to take about 20 milliseconds.
 
Patrick Johnson said:
As I've said before, Jim, nobody but you much cares what the "score" is between us - least of all me. I restated my point because it got buried beneath your pile of pointless nitpicking, not to win some contest with you.

Stick to pool.

pj
chgo
Click to expand...

Who said anything about keeping score? Do you have a "special friend" who whispers such things in your ear?

And you are the NITPICK WORLD RECORD HOLDER!

Who else but you has EVER nitpicked about whether the word "from" means a billionth of a second BEFORE the millisecond of tip to ball contact or after it????????????

And every time you blurt out your occasionally nonsensical pontifications disguised as actual knowledge....like when you stated that the forearm should always be held vertical at address...and you are CORRECTED...you resort to your whiny little protestations that people are NITPICKING.

Actually, your skulking off to hide behind your "nitpick defense" instead of being a man and simply admitting that you were in error would be pretty entertaining if it wasn't so sad.

Jim
 
Bob Jewett said:
The acceleration of the stick is expected to have a large negative peak at the instant it hits the cue ball, but that is not evident on the red trace. Either it was too brief to be captured, or it was so large it overloaded the recording system. The re-acceleration does seem to be visible as a positive peak in the red trace after tip-ball impact. It is expected to take about 20 milliseconds.
Click to expand...

And Bob, since your Jacksonville Project article implicated the shooter's hand and arm regarding the acceleration from the negative peak would it be correct to assume that different shooters with different hand and arm weights would produce a different plot...all other things being equal?

Regards,
Jim
 
Well, I glad to see you got this thread back to acceleration, (the original question asked) before I had changed it to a kicking question.

Some interesting thoughts here.

Sorry Bob for the earlier diversion.(you were right)
 
Bob:

I used ADXL 311L's. Max bandwidth for that device is 5 kHz, but I limited it to 500 Hz.
 
JohnnyP said:
Bob:

I used ADXL 311L's. Max bandwidth for that device is 5 kHz, but I limited it to 500 Hz.
Click to expand...
That might explain it. To get a good result during the tip-ball impact, you need a bandwidth of over a kilohertz. It might also be a problem of overload, since the cue stick has a 50% reduction in velocity in about 1 millisecond. I think that's a much, much larger acceleration than anything on the plot.
 
Me:
Johnny, what are the time intervals on your chart?

JohnnyP:
Horizontal axis is 100 msec per division.
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So the whole chart is a little over 1/2 second long (going left to right), each vertical division is 1/10 of a second and the amount of time the tip is actually in contact with the ball is 1/100 of one of those divisions, or less than the thickness of a single line, right? I just wanted to put that in perspective for myself.

I appreciate you going to the trouble of measuring this and posting it. Do you plan to try it at the higher frequency Bob suggested, so we can see more clearly what happens at impact?

pj
chgo
 
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I'll look into it. It's gooped up with RTV, so it will be a beotch to change the response.
 
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