Summary: David Alciatore, PhD ("Dr. Dave") ILLUSTRATED PRINCIPLES
"Just How Big are the Pockets, Anyway? Part II"
Note: Supporting narrated video (NV) demonstrations, high-speed video (HSV) clips, and
technical proofs (TP) can be accessed and viewed online at billiards.colostate.edu. The
reference numbers used in the article (e.g., NV 3.15) help you locate the resources on the
website. You might also want to view the resources from a CD-ROM. See the website for more
In last month's article, I presented several principles concerning factors that contribute to
making some shots more difficult than others based on speed, angle to the pocket, and pocket
contact point. All of the principles and effects I presented can be summarized with a collection of
graphs I will show in this and next month's articles. All of these graphs were generated from
detailed, physics-based, technical analyses (see TP 3.5 and TP 3.6). Being the compulsive
analytical person that I am, it wasn't good enough to just have an intuitive feel for some of the
principles I described and demonstrated in last month's article. I wanted to know exactly how
much a shot's margin for error changes with angle and distance from the pocket and with speed.
The diagrams in this article show some of the results of this detailed analysis. The technical
analyses won't be of interest to most readers (unless you are a geeky engineer or physicist), but
the results should be very interesting to most readers.
TP 3.5 Effective target sizes for slow shots into a side pocket at different