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Calculus of the perfectly centered break of a perfectly aligned pool ball rack

Posted 10 years ago
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POSTED BY: Jim Belk
11 Replies

This is beautiful.

Which version of mathematica are you using? I tried your notebook in M10.0.2 and it threw errors and the manipulate didn't work as your animated gif shows that it does.

$System is "Mac OS X x86 (64-bit)"

POSTED BY: W. Craig Carter

I attached corrected for V9+ notebook to this post.

I think Jim is using earlier versions. To make this work in V9+ the function NDSolve should have corrected method specification

NDSolve[..., Method -> {"DiscontinuityProcessing" -> False}]

and it is better for Manipulate to have SaveDefinitions -> True.

Attachments:
POSTED BY: Vitaliy Kaurov

This comment on the reddit thread:

Assuming the two corner balls don't bounce back and interfere, it looks like this break would sink two of the balls in the side pockets on an 8 foot table: https://dl.dropboxusercontent.com/u/27794628/BilliardsHertz2.gif

links to the nice simulation below.

enter image description here

POSTED BY: Vitaliy Kaurov

This is now is very popular - a top thread - on reddit physics with 97% upvoted > 300 points (currently):

http://redd.it/2rsqni

POSTED BY: Sam Carrettie
Posted 9 years ago

Cool, excellent work !

Suddenly, I come up with one interesting question for billiards. As Vitaliy shows the full range of billiard table, is that possible to calculate the possibility, that all balls fall into holes just by one-shot-break. Possible or not possible, for 15 balls, can it be proved or verified by mathematics.

I mean, itÂ’s just from perfect physical and theoretical prospective. It will be very hard for human and need high precision, not for practice. I don't know, if any professional player has ever done before, or any recording for this very rare things.

Maybe, A further question, how many balls (those balls consist of an initial triangular billiard) can be done by one-shot-all-fall.

Anyway, I think the current model can be use to analisys bowling ball as well. Bowling game is simple than billiard, no bounce and no trajectory.

POSTED BY: Frederick Wu

Given how many youngsters play pool, this could certainly be something that may give teachers a few ideas for an illustration that gets students to pay attention. It has a lot of 'real-world' relevance for them, I think it's fair to say :)

POSTED BY: Richard Asher

Why are there no attachments anymore? Jim, your Bard webpage also seems to have disappeared. Do you still have a copy of this notebook/Manipulate? I'd love to play with and add to it!

POSTED BY: Peter Barendse

looks like the attachment here disappeared

POSTED BY: Peter Barendse

Your article is very informative. As a billiards player I wonder what the best technique to break the rack in order to sink a ball, thus remaining the shooter. I'm assuming your analysis does not include horizontal rotation (english) of the cue ball as it hit the head ball of the rack. Also, can you evaluate a break from the rail at the first diamond as many players shot from this position. Is it the best position to sink at least one ball (not the cue ball)?

POSTED BY: Chuck Fingerman

Or anyone has the notebook of BilliardHertz.nb from Professor Jim Belk? It is appreciated that someone can share the 2014 code once again!

Even if it is a Mathematica 8.0 version is fine! As I have kept a Mathematica 8.0 in an old computer, I can run the Mathematica 8.0 code robustly!

POSTED BY: Ching Li

The code is available again in the main post. Thanks to Dr. James Belk for providing it.

POSTED BY: Ahmed Elbanna
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