How would a hollow cue ball play?

garczar

AzB Silver Member
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lets up it a little

and say the hollow cue ball can carry an electrical charge and be magnetized

and magnetize the table.

is it possible to approximate traditional ball dynamics with a hollow ball set and some computing device to make the adjustments in ball motion.

a pool table in space would have to simulate some things.

I don't think NASA or spaceX would put billiards equipment in the payload for free.

maybe China or UAE
zzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzz
 

Patrick Johnson

Fish of the Day
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FYI, here in the Northeast, BU denotes Boston University, where, by the way, Martin Luther King Jr was once a student.
I lived in Brookline for a couple years in the early 70s - had to think for a minute to be sure I wasn’t thinking of that BU.

pj
chgo
 

Bob Jewett

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Well actually looking at the picture, I think my prior assumption that Aramith used a lower density material for the core of the ball to make up for the magnetic layer's presumed higher density is incorrect. It looks like they just use regular balls for the core, probably the ones that come in undersize due to manufacturing variations.
Manufacturing defects are going to be a lot less than the 4mm or so thickness of that shell unless someone leaves a set in the polisher over the weekend. Maybe rejects from a set of 2-inch balls.
 

Bob Jewett

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... Changes in MMI would affect anything involving changes in spin ... the curve shape of a masse shot...
I can see that the extent of the curve might change, but wouldn't it remain a parabola? Would Coriolis's rule for masse shots still hold?
 

Bob Jewett

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Making a real "shell ball" is a problem. I think it would tend to ring when struck in a way that a solid ball does not. To prevent that, you need a rigid, massless foam filler.

Unless I slipped a digit, a steel shell the size of a pool ball would need to be about 2mm thick to get to 168 grams, which comes pretty close "all the mass on the surface".
 

justnum

TesticularCancer Survivor
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Making a real "shell ball" is a problem. I think it would tend to ring when struck in a way that a solid ball does not. To prevent that, you need a rigid, massless foam filler.

Unless I slipped a digit, a steel shell the size of a pool ball would need to be about 2mm thick to get to 168 grams, which comes pretty close "all the mass on the surface".

a hollow ball does not have to be empty, there can be cavities which could assist in adding weight. a draw shot on a hollow ball could turn into a jump, i didnt do calculations.

collisions with a hollow shell of equal mass resulting in same effect as regular ball? I have doubts.
 

lfigueroa

AzB Silver Member
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Compared to a normal, solid cue ball, what differences would there be in the way a hollow cue ball of the same size and weight plays? Would the thickness of the hollow ball’s shell matter?

Thanks for your insights.

pj <- just curious
chgo


Just imagine a ping pong ball hitting a golf ball.

lou Figueroa
 

Patrick Johnson

Fish of the Day
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Compared to a normal, solid cue ball, what differences would there be in the way a hollow cue ball of the same size and weight plays? Would the thickness of the hollow ball’s shell matter?

Thanks for your insights.

pj <- just curious
chgo
Just imagine a ping pong ball hitting a golf ball.

lou Figueroa
I said "of the same size and weight", so it would have to be a pretty heavy ping pong ball. :)

pj
chgo
 

Bob Jewett

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Do you mean make a ringing sound?

pj
chgo
Yes, like a bell. If the ringing is fairly slow, like one cycle or less in the time the tip is in contact, a fair amount of energy can be lost in the tip-ball contact. If the ringing is a fairly high frequency, like many cycles in a millisecond, then not much energy goes into the ringing.

A 2mm-thick steel surface ought to have fairly high resonant frequency.
 

Patrick Johnson

Fish of the Day
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Yes, like a bell. If the ringing is fairly slow, like one cycle or less in the time the tip is in contact, a fair amount of energy can be lost in the tip-ball contact. If the ringing is a fairly high frequency, like many cycles in a millisecond, then not much energy goes into the ringing.

A 2mm-thick steel surface ought to have fairly high resonant frequency.
So the ball would oscillate like a bell and that could counteract some of the tip-ball energy? Cool. Would the same dynamic apply to ball-ball collisions?

pj
chgo
 

iusedtoberich

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Manufacturing defects are going to be a lot less than the 4mm or so thickness of that shell unless someone leaves a set in the polisher over the weekend. Maybe rejects from a set of 2-inch balls.

I believe, but not certain, that when steel bearing balls are ground to final size, they are then sorted. Some come out smaller, bigger, perfect, etc., due to normal manufacturing variations. And then the sorted balls are sent to the cooresponding bearing assembly. Perhaps making pool balls is similar. If some are a bit undersize after the sorting, those would be good candidates to use for the inside of a cb. Just my guess...

Edit: Because they are too small to meet the spec of a standard set. But I'm talking a few thousandths of an inch. They would then be made much much smaller for the magnetic cb purpose. This idea would save them from being scrap.
 
Last edited:

Rickhem

AzB Silver Member
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Quote:
Originally Posted by Bob Jewett View Post
Yes, like a bell. If the ringing is fairly slow, like one cycle or less in the time the tip is in contact, a fair amount of energy can be lost in the tip-ball contact. If the ringing is a fairly high frequency, like many cycles in a millisecond, then not much energy goes into the ringing.

A 2mm-thick steel surface ought to have fairly high resonant frequency.


So the ball would oscillate like a bell and that could counteract some of the tip-ball energy? Cool. Would the same dynamic apply to ball-ball collisions?

pj
chgo


This is what I meant by the "trampoline effect", and how that would need to be eliminated. (also known as the Coefficient of Restitution, or COR value) If not, then the stored energy of an impact, be it from cue tip, or ball-ball, would be returned in a much different force than a standard elastic collision. This principle, the COR value, is used for baseball and softball bats, balls, golf clubs and balls, and I'm sure lots and lots of other similar sporting equipment. And while it would ideally need to be eliminated for a direct comparison to a solid cue ball, I sincerely doubt that woud be possible. Even a core of something super light, say carbon fiber, surrounded by the weight carrying layer, and then finally coated by the phenolic layer to match the surface characteristics of a "standard" cue ball (a moving target to be sure), would still have a different COR value than a standard cue, and that ringing, or resonance, or deflection, or whatever you'd call it, would change the dymanics of the experiment, at least as much as I'm interpreting it.
 
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