Margin of error

[nine_ball6970]

I have been thinking about a comment in Mark Wilson's book. I am paraphrasing but he says that a big difference between pros and everyone else is the ability to strike a point on the cue ball extremely accurately repeatedly.

Say that you are aiming to make a ball using center cue ball. I know that if the cue ball and object ball are farther apart, the smaller the area you have to strike the object ball to make it. Have any tests be done to show how much each millimeter away from center cue ball affects the cue ball path over various distances?

 

[Bob Jewett]

I have been thinking about a comment in Mark Wilson's book. I am paraphrasing but he says that a big difference between pros and everyone else is the ability to strike a point on the cue ball extremely accurately repeatedly.

Say that you are aiming to make a ball using center cue ball. I know that if the cue ball and object ball are farther apart, the smaller the area you have to strike the object ball to make it. Have any tests be done to show how much each millimeter away from center cue ball affects the cue ball path over various distances?

The basic accuracy required can be found fairly simply but it does require a little geometry to understand why it is true. If you measure the distance from the object ball to the pocket in diamonds and the distance from the cue ball to the object ball in diamonds and multiply those two together, you get the difficulty of the shot. For example, if the cue ball is on the line and a ball is half way to the corner pocket six diamonds away, the two distances are 3 diamonds. Multiply those together and you get 9. That's the difficulty of the shot. The fairly simple geometry (high-school level, if you remember it), says that you have about 10mm divided by the difficulty for error in placement left and right of your two hands. That's for an average 9-foot table.

10mm/9 is about 1mm which is about the accuracy required from your mechanics. That's half the thickness of a nickel. The simple result is that if your bridge is in exactly the right position, your backhand must be correct within the width of a nickel to make that long a shot.

If you include the concepts of pivot point and squirt and backhand english, you can put all the accuracy requirement on your front hand if you choose the right bridge length for the length and speed of shot you're planning. In that case, the accuracy of your front-hand placement is more strict by a factor of 2 or 3.

 

[Careyp74]

I know that if the cue ball and object ball are farther apart, the smaller the area you have to strike the object ball to make it.

The area is still the same, that doesn't change as long as the object ball is still the same distance from the pocket. What does change is the ability to send the cue ball to that area. The closer the cue ball is to the object ball, the greater the angle of available shot directions where you can hit the cue ball and make the object ball. From further away, the allowable contact area is still the same, but now the angle of available angles is smaller.

Your best bet for answering your question would be found here somewhere.

http://billiards.colostate.edu/

This one might touch on it

http://billiards.colostate.edu/bd_articles/2005/jan05.pdf