Hi everyone. I have this doubt: when the cue ball impacts the ojective ball and then it touches the rail, the go out line would be represented by the angle and the english. But the cue ball has to arrive with this english to the rail? If that affirmation is true we have to analize how the impact on the objective ball will result on the cue ball? So we can calculate the line the cb will go.
Cue Ball reaction after impacting a rail.
- Thread starter giulichajari
- Start date
Yes, you are correct. The amount of spin the cue ball has on it, the speed the cue ball is traveling and the angle it is coming into the cushion at are the three factors that will determine exactly the angle it will come off. A fourth factor would be the kind of cloth on the table and how new/old the cloth is. Trial and error is the best way to learn this.
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Spin tends to have the strongest influence on exit angles. There is a subtle but important variable in the problem as stated and that is, a caroming ball may be bending and the actual entry line to the cushion may differ greatly from the geometric tangent line to the cushion.
To predict the line out from the cushion you need to know the speed, spin and direction of the cue ball just before it hits the cushion. In addition you need to know a lot about the cushion and for the final direction of the cue ball you need to know about the cloth on the bed of the table.
So far as I know, there is no good theory of ball/cushion interaction. Or at least not good enough to predict all the different shots that can happen. Simulation software for that works from stored values so far as I know.
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Spin ONLY has an effect on exit angles. Tangent line combined with draw/follow is what affects the entry angle. On anything more than a very slowly struck ball, with extreme spin.
Edited to clarify "side" spin. Oh, wait. That was made clear by differentiating draw/follow separately. But some people's chirrens feel the need to "correct".
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Biloxi Boy
Man With A Golden Arm
And what effect does skid have?
I would think skid might kill the rock somewhat causing it to slide along the geometric tangent but most of the overthrow happens on the object ball.
Studying angular properties of physics has not been added to billiard literature.
Everything on a pool table is designed for physics demonstrations.
The moment of inelastic collision is well defined in a calculus with physics college textbook. That is the technical term when the ball and cushion are connected.
There are many research level studies on collisions of equal sized balls. Its curious if the pool industry understands the application to higher mathematics.
Everything on a pool table is designed for physics demonstrations.
The moment of inelastic collision is well defined in a calculus with physics college textbook. That is the technical term when the ball and cushion are connected.
There are many research level studies on collisions of equal sized balls. Its curious if the pool industry understands the application to higher mathematics.
If you go out and hit 1,000,000 balls you will have the theory of speed, spin, and rail contact embedded in your head to the degree that you won't need a theory to show you the way.
Biloxi Boy
Man With A Golden Arm
I agree completely. There is no substitute for experience, which brings to mind one of the many definitions of an "expert" I have heard through the years -- "can tell you 99 different ways to make love to a woman but has never had a girlfriend",
Skid is more a result than a cause. (I assume you mean a sliding cue ball after cushion contact rather than the other meaning of skid which is a bad contact.) A visibly sliding cue ball is usually due to slippery (new) cloth. Carom players hate it because it is hard to predict and changes quickly as the cloth wears in even over a few days.
If you practice a system you might only need to hit 500,000 (or so) balls before "the way" is embedded in your head.
pj
chgo
Biloxi Boy
Man With A Golden Arm
Excuse my lack of clarity as I know nothing about it except through observation and I am certain my nomenclature is incorrect, but here goes: a ball maintains traction on the cloth allowing spin to take hold or a ball loses traction and "skids" in which case spin has no effect on the path of travel. Once the speed of skidding ball slows and traction exists, then spin has a result. I seem to observe the "transition" between the two on banked object balls coming off a rail when the object ball was on the rail before impact.
I always felt that skid was related to speed or acceleration, but, as I said, I know little or nothing about the subject.
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Not sure if I understand what you are saying.
Velocity will effect the exit angle as well, with a hard strike exiting shorter than a softly struck ball.
Spin will effect the path after leaving the rail so either take I come up with for your statement.....I still come up with NO.
On normal cloth/rails a ball banked straight into the cushion that is rolling comes off rolling the new direction almost immediately. If the cloth is new and slippery, the ball will come off the cushion with the same spin it had going into the cushion. But that is now backspin because the direction of the ball has changed. As the backspin wears off, the ball is simply sliding at some point before it starts to roll in its new direction.
This action looks really weird. I think it's commonly called slide or skid.
But we aren't talking about other things that can affect the exit angle. The statememt was specifically about (side)spin only affecting the exit angle, not the entry angle.Not sure if I understand what you are saying.
Velocity will effect the exit angle as well, with a hard strike exiting shorter than a softly struck ball.
Spin will effect the path after leaving the rail so either take I come up with for your statement.....I still come up with NO.
A light falling on the table in the middle of a stroke can also affect the entry/exit angle, but I did not feel the need to address that, either. And (side)spin as a general rule, has no affect on entry angle. Backspin and forward spin, do.
My statement was ONLY about what effect SPIN has. Of COURSE I know there are other elements that ALSO affect the exit angle.
Put another way relevant to your response..Not sure if I understand what you are saying.
Velocity will effect the exit angle as well, with a hard strike exiting shorter than a softly struck ball.
Spin will effect the path after leaving the rail so either take I come up with for your statement.....I still come up with NO.
I did not say "ONLY spin has an effect on exit angles.", I said "Spin ONLY has an effect on exit angles." (Clarifying that I was referring to "side" spin.) Where that ONLY is applied in the sentence has a big effect on meaning. Don't put words in my mouth based on lack of reading comprehension.
And nobody ever said that spin does not affect the path of the ball after it leaves the rail. This was only ever about exit/entry angle. Anybody who has read even a few pages in a book on pool knows the cue ball with draw applied bends backwards off the exit angle after leaving the rail, or bends forward with follow.
Neither of these actions has anything to do with the actual entry/exit "angle". Backspin/forward spin can affect the entry angle before it hits the rail, but again, that is not what my statement was meant to address.
Byrne's Standard Guide to Pool and Billiards explains the physics quite nicely.
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