Energy transfer from cuetip to whiteball

tim913 said:
I think it’s more than just the speed of the tip when making contact. If you take it from one extreme to the other it makes a big difference in energy transfer. Example:
If what’s behind the tip is a feather vs a steel rod and the tip speed is the same at CB contact the feather will collapse on contact and not transfer much energy to CB whereas the steel rod will not collapse
If there’s a difference in extreme to extreme there has to be a difference at all points in between although it be minuscule .
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Yeah, great... If you ever play pool with a feather or a steel rod.
 
Not Dead Ted said:
Or maybe not. I can't access the article without forking over some dough, but it looks interesting:

Energy loss in cue-ball collisions​

Rod Cross

Published 6 September 2021 • © 2021 European Physical Society. All rights, including for text and data mining, AI training, and similar technologies, are reserved.
European Journal of Physics, Volume 42,Number 6

Abstract​

When one object collides with another, the collision results in a loss of kinetic energy. The energy loss occurs mainly in the small volume of material that is compressed in the vicinity of the contact point. The effect was examined using a billiard cue with different tips. The resulting ball speed was found to vary strongly with the type of tip used, indicating that a large fraction of the energy loss occurred in the tip rather than the cue itself. The player’s hand alters both the effective mass of the cue and the coefficient of restitution.
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IIRC this is one of the reasons Meucci's Myth Destroyer data is often considered flawed because the cue was held tightly, not like a hand's soft tissue.
 
tim913 said:
I think it’s more than just the speed of the tip when making contact. If you take it from one extreme to the other it makes a big difference in energy transfer. Example:
If what’s behind the tip is a feather vs a steel rod and the tip speed is the same at CB contact the feather will collapse on contact and not transfer much energy to CB whereas the steel rod will not collapse
If there’s a difference in extreme to extreme there has to be a difference at all points in between although it be minuscule .
Click to expand...
a stiffer shaft may provide more ball speed buts its tiny. i noticed this when trying out various cf shafts, its there but not enough to change how you play. speed is the main thing in energy transfer.
 
garczar said:
That's all fine if that's what the shot requires. A short/quick stroke cannot produce the speed needed for,say, a long draw shot. That requires speed that the short quick stroke will never generate.
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I think this is an overstatement. Take a look at this clip of Alex using his little punchy stroke to get some excellent draw.


Now we aren’t all Alex and when trying for good draw a longer stroke is better for most of us, but I think it’s fair to say a short quick stroke can produce excellent draw.
 
GideonF said:
I think this is an overstatement. Take a look at this clip of Alex using his little punchy stroke to get some excellent draw.


Now we aren’t all Alex and when trying for good draw a longer stroke is better for most of us, but I think it’s fair to say a short quick stroke can produce excellent draw.
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Balls were close together on real fast cloth, Not a whole lot of juice need to do this. Its true speed can be generated different ways but on this particular shot not a lot was needed. Had those balls been further apart(and/or on old cloth) you would have seen a completely different delivery.
 
Not Dead Ted said:
Or maybe not. I can't access the article without forking over some dough, but it looks interesting:

Energy loss in cue-ball collisions​

Rod Cross

Published 6 September 2021 • © 2021 European Physical Society. All rights, including for text and data mining, AI training, and similar technologies, are reserved.
European Journal of Physics, Volume 42,Number 6

...​

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Rod has gotten several things wrong. For example, he felt that cue ball deflection was due to minor miscues. It's not.

The flesh of the hand is too soft to let the hand have any significant influence on the cue stick during the contact time. The hand is roughly 100 times softer than the tip/ferrule, as measured by high speed videos multiple times. That means that a very firm grip, or accelerating at the time of tip-ball contact might increase the effective mass of the stick by 1%, but that's not enough to do anything that can't be done by a very slightly faster stroke.
 
garczar said:
IIRC this is one of the reasons Meucci's Myth Destroyer data is often considered flawed because the cue was held tightly, not like a hand's soft tissue.
Click to expand...
The original Iron Willie (Predator's machine) had a very rigid, tight grip, so most of the mass of the swinging mechanical arm was added to the stick. This was temporarily solved during the Jacksonville Experiment by wrapping the butt of the cue with bubble wrap.
 
garczar said:
Balls were close together on real fast cloth, Not a whole lot of juice need to do this. Its true speed can be generated different ways but on this particular shot not a lot was needed. Had those balls been further apart(and/or on old cloth) you would have seen a completely different delivery.
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I’ve watched Alex play a lot and his stroke is always short. I don’t have another example handy (searching only found me that one example), but I’m pretty confident Alex’s delivery would not be “completely different” if he’d needed more draw.

Would it have been a bit longer? Probably. But he’s never going to have the long stroke we think of for big draw shots. And it’s likely he can’t get the massive draw that a Shane or Fedor can with their longer strokes.

Again, I’m not saying we should all punch draw and expect to get massive draw. For most of us we can’t achieve that kind of acceleration in a short window, especially while maintaining accuracy.
 
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