Billiards Digest May, 2009 David Alciatore, PhD ("Dr. Dave") ILLUSTRATED PRINCIPLES Summary: Billiards Digest May, 2009 David Alciatore, PhD ("Dr. Dave") ILLUSTRATED PRINCIPLES "Draw Shot Physics - Part II: examples" Note: Supporting narrated video (NV) demonstrations, high-speed video (HSV) clips, and technical proofs (TP), and all of my past articles, can be accessed and viewed online at billiards.colostate.edu. The reference numbers used in the article help you locate the resources on the website. If you have a slow or inconvenient Internet connection, you might want to view the resources from a CD-ROM or DVD. Details can be found online at: dr-dave-billiards.com. This is the second article in a series on draw shot physics. Last month, we looked at some of the basics and listed a set of conclusions from a thorough physics analysis (TP B.8). This month, I want to present some detailed results and show some specific examples that illustrate some of the conclusions. With a straight-on draw shot (with no cut angle), the draw distance is determined solely by the amount of spin the cue ball (CB) has at contact with the object ball (OB). It is important to distinguish between how much spin the CB has off the tip and how much it has at OB contact, after some spin is lost due to "drag" on the cloth. Diagram 1 shows how much spin the cue delivers to the CB for different tip offsets. With a small offset (i.e., close to a center- ball hit), the CB will have very little spin (point "A"). Obviously, as you increase tip offset, the amount of spin increases. At point "B" (at about 30% tip offset), you get about 50% of maximum spin; and at point "C" (50% offset), you get about 75% of maximum spin. Maximum spin occurs Collections: Engineering