Physics of Cue Striking Ball

14 December 2016

"Uncovering the Cue Mysteries" from the June 1999 edition of Billiards Digest, is an older, but still relevant and interesting, look at the physics of what happens when the cue strikes a ball.


Some excerpts from the article include some observations that are worth noting:

"Significant energy is lost in the tip, perhaps as much as 30 percent. For a break stick, you want to lose as little energy as possible. The suggestion from the video is that work on the tip is more likely to improve a break stick than anything else."

"Another major contribution of the tape is an improved under- standing of how squirt develops. It is clear now that all sticks must have squirt or deflection on spin shots because movement of the front part of the stick to the side as the tip rotates sideways with the spinning ball must have an equal and opposite motion to the other side by the cue ball. However, there is no way to control how much sideways speed the stick gets — that's determined by the amount of spin used — but it is certainly possible to reduce the effect by reducing the weight of the front part of the stick. This result bears out what a lot of people have been saying for some time: balance, length and weight aside, all of the playability of a stick is in the shaft."

"Miscues are quite a story. It is possible for the cue stick to hit the cue ball four times on a miscue, two or three times with the cue tip and once or twice with the ferrule. In fact, the slapping sound you hear on a miscue is exactly that — the ferrule hitting the cue ball. This means that most miscues (not all — it doesn't always happen) are fouls and if they happen in 9-ball, it should technically result in ball-in-hand. This will require a change to the rules someday, since it's probably not a good idea to make the referee use a high-speed cam- era to tell when a foul has occurred."

Get the full article at Uncovering the Cue Mysteries