Cue Angle vs. Squirt Amount?
- Thread starter Patrick Johnson
- Start date
The pics below show the same cue hitting the CB on the same spot while traveling in the same direction.
The cue on the left is stroked normally, straight ahead parallel with the CB's no-squirt path (the dotted white arrow).
The cue on the right is also stroked parallel with the CB's no-squirt path, but with the cue angled as shown (don't ask me how to do that; this is a thought experiment).
Which one produces more squirt (compared with the no-squirt CB path)?
pj <- not a quiz - I don't know the answer
chgo
View attachment 63025
Differs from shaft shaft end weight will vary squirt amount
1
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To compare the different motions without those complications I'm assuming it's the same cue.
pj
chgo
The best answer I can come up with - and I'm not completely happy with it myself - is that in the transverse direction, the cue acts like a very weak spring. With a weak spring, it takes much more deformation of some sort (compression, tension, bending...) to cause the spring to resist the deformation by generating a certain specific amount of force, as compared to a strong spring. With a cue, there's a large difference in its transverse versus longitudinal "springiness."
Thus for something traveling due North that encounters something that opposes its motion, the net force on that obstruction will be the vector sum of the reaction forces.
Jim
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The pics below show the same cue hitting the CB on the same spot while traveling in the same direction.
The cue on the left is stroked normally, straight ahead parallel with the CB's no-squirt path (the dotted white arrow).
The cue on the right is also stroked parallel with the CB's no-squirt path, but with the cue angled as shown (don't ask me how to do that; this is a thought experiment
Which one produces more squirt?
pj <- not a quiz - I don't know the answer
chgo
View attachment 63025
If the intended path of CB is the dotted line then the angled cue should be coming across the CCB point. For your pictured shot the angled cue should be coming from the right side into the point you are hitting.
PJ,
I'm trying to simulate a swoop stroke at the same angle of attack as a straight stroke, to explore how the squirt for both might affect the outcome. [NOTE: I've replaced the pic of the angled cue with a more realistic one that has a smaller angle.]
The white arrows are the intended no-spin path of the CB (I edited the OP to be clear about that), so it's assumed that the CB will actually go somewhere to the right of that - will it go different directions each way? Why?
My assumption is that the angled cue moving as shown above is a fair simulation of a swoop stroke at the same point-of-contact. Do you agree?
I think Jal covered it fairly well. With the shot in your 2nd diagram above, I think the dashed arrow should be in the direction of the cue (since that is the direction of the main force or "line of action" of the shot), and I think it should be labeled "no squirt or swoop action" or something like that. The simulated swoop does create a small sideways force on the CB perpendicular to the cue, but this force is not as large as some people might think, for the reasons Jal explained. As demonstrated in the swoop experiment video, the swooping motion will push the CB a little to the left of the "no squirt or swoop action" direction of the cue. And if the cue (or "line or action") is pointing to the left of the center of the CB, there will be squirt which will push the CB a little to the right of the "no squirt or swoop action" line.
So the effects work in opposite directions. That's why one of the swoop advantages listed on the stroke swoop resource page is:
The sideways swiping motion (especially if it is fast in comparison to the forward speed of the cue) helps provide slightly more squirt (cue ball deflection) aim compensation than is provided by a pre-stroke BHE pivot. And if one uses a non-LD-shaft (especially with a long bridge length), this slight extra squirt compensation might be helpful (assuming they haven't already adjusted their aim and alignment to intuitively compensate for squirt, swerve, and throw, as most pros and top players do).
Regards,
Dave
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Nice experiment on swoop stroke Dr Dave! I just saw the video you made linked in your post above.
I would also add the following:
Let's assume a swoop stroke is being used and the tip is hitting the CB with a perceived center-ball hit (i.e., with the cue pointing through the center of the CB at contact), as shown in figure "a" of the diagram below. Creating a sideways force on the CB with the tip requires friction, and friction requires "normal" force (in the direction of the cue, perpendicular to the CB surface). If you try to swoop or swipe with significant speed (in comparison to the forward speed of the cue), the normal force won't be large enough to create very much sideways friction between the tip and ball, and the CB won't move forward with much speed. And even if more friction were possible, the sideways or transverse "endmass" and stiffness of the shaft is not ample enough (as compared to the longitudinal mass and stiffness of the cue along the main "line of action") to support the force over the incredibly short contact time. If it were, squirt (CB deflection) resulting from off-center hits would be much larger than it is with a typical cue, which would make it impractical to play shots with any sidespin at all, with or without a swoop stroke.
Again, if anybody thinks it is possible to create maximum sidespin using a swoop stroke with the tip contact point being close to the "perceived" center of the CB, please try the experiment described in my swoop article and starting at the 6:34 point in my swoop video, being careful to check the chalk mark on the CB after each shot. It ain't possible!
Regards,
Dave
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Thanks. FYI, much more info (and additional demonstrations) can be found on the stroke swoop resource page.
Enjoy,
Dave
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So you're saying that if you want to swoop, the tip should follow a sinusoidal-like path on the way to the CB. Is that the moral?
Thank you kindly.
...nice pic! :grin:
Jim
This pic is not objectively definitive.
One could just as easily see the the line to the left as the science line.
It would seem that 'science' has limitations & is not very adept at making objectively definitive memes.:wink:
Einstein was very good at thinking out of the box & formulating concepts but not a very good mathematician & following those dictates & at times needed help with the actual math.
A simple definition of science is the ACTIVITY of STUDY.
Hence Science always has an open mind & is ever studying.
Best 2 All.
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