General player understanding of side/english usually relates to the aim line through center ball. That line extends to the target, an object ball when potting, which is roughly the ghost ball location. Paradoxically the physics of spin on the object ball doesn’t care about the target line. When parallel english is used the line and direction of force will coincide with the target line. When any other version of side application is used, the direction of force and its relationship to a parallel line through the center of mass are the common denominator. FHE and BHE each have lines of force that don’t care about the shot line in their calculations. Deflection calculations are a different matter. The relationship between contact point, contact angle, approach angle, tip shape, chalk and coefficient of friction all factor into eventual force dynamics after impact, including deflection calculations, but the original target line is not found in those equations, except with parallel english.
Basically the line of force through the ball when side is used, has a parallel relationship to a line running through the center of mass. In other words the physics math is different for FHE than for BHE or parallel english, because the line paralleling each type of english, through the center of mass, is on a different plane. Parallel english finds the force line through the center of mass coincides with the target line. The paradox is that regardless of which type of english is used the reference used has been the target line, usually measured in tips of english. But tips of english from the ghost ball line won’t tell you the length of the torque line. In other words it doesn’t tell you how much side is really being applied on the ball, except when using parallel side.
A closer look is enlightening. We know that the cueing angle through the ball is related in physics math to a parallel line running through the center of mass, not a spot on the surface. The center of the ball is the true reference point. The distance of the cueing line to the paralleling line through that center is a torque arm, the length of that line is used in spin calculations. I call it simply the torque line.
There is a problem in perception because the ghost ball line, not the paralleling line through the center, has been used as the reference. Using that as the perspective has all perceived lines of english radiating from or paralleling the ghost ball line. Using those diverging lines the game has missed a whole range of angles with side, not currently used in play. The implications are huge.
Our fixation on the target line, when describing side, is only relevant when parallel english is used. In essence every type of side’s, force line, is parallel in nature, only that parallel line, doesn’t correlate to the target line. Various deflection, curved ball travel dynamics, combined with aim adjustments, and margin of error characteristics, allow balls to arrive in the same impact zone and pocket balls, despite our understanding reference being flawed.
If anyone is interested I will explain the missed versions of side, how to apply them, how to adjust for each and their uses in potting and playing position. There is some basic geometry, mainly ratios, in the explanations but no real math otherwise.
Some references to Dr. Dave physics results will be used as references for validation.
ADDENDUM: A poster on a later page suggested a glossary at the beginning to make reading easier.
Parallel English - aiming technique when using sidespin where the cue is placed parallel to the line of aim for a center-ball hit (with no sidespin) resulting in no compensation for CB deflection (e.g., for shots where swerve is expected to cancel the effects of squirt and throw, resulting in no net CB deflection, or where the amount of resulting pocket cheat is acceptable).
Corollary - Lines that are not parallel will intersect at some point
Divergent English - where the cue placement is not parallel to the center ball aim line. The line the cue is on will cross the center ball aim line on the player side of the cue ball.
BHE - a type of divergent english where the cue line diverges from the current ball aim line at the bridge
FHE - a type of divergent english where the cue line diverges from the current aim line at the grip location
Convergent English - where the cue placement is not parallel to the center ball aim line. This line converges with the current aim line on the other side of the cue ball from the player aim position.
Basically the line of force through the ball when side is used, has a parallel relationship to a line running through the center of mass. In other words the physics math is different for FHE than for BHE or parallel english, because the line paralleling each type of english, through the center of mass, is on a different plane. Parallel english finds the force line through the center of mass coincides with the target line. The paradox is that regardless of which type of english is used the reference used has been the target line, usually measured in tips of english. But tips of english from the ghost ball line won’t tell you the length of the torque line. In other words it doesn’t tell you how much side is really being applied on the ball, except when using parallel side.
A closer look is enlightening. We know that the cueing angle through the ball is related in physics math to a parallel line running through the center of mass, not a spot on the surface. The center of the ball is the true reference point. The distance of the cueing line to the paralleling line through that center is a torque arm, the length of that line is used in spin calculations. I call it simply the torque line.
There is a problem in perception because the ghost ball line, not the paralleling line through the center, has been used as the reference. Using that as the perspective has all perceived lines of english radiating from or paralleling the ghost ball line. Using those diverging lines the game has missed a whole range of angles with side, not currently used in play. The implications are huge.
Our fixation on the target line, when describing side, is only relevant when parallel english is used. In essence every type of side’s, force line, is parallel in nature, only that parallel line, doesn’t correlate to the target line. Various deflection, curved ball travel dynamics, combined with aim adjustments, and margin of error characteristics, allow balls to arrive in the same impact zone and pocket balls, despite our understanding reference being flawed.
If anyone is interested I will explain the missed versions of side, how to apply them, how to adjust for each and their uses in potting and playing position. There is some basic geometry, mainly ratios, in the explanations but no real math otherwise.
Some references to Dr. Dave physics results will be used as references for validation.
ADDENDUM: A poster on a later page suggested a glossary at the beginning to make reading easier.
Parallel English - aiming technique when using sidespin where the cue is placed parallel to the line of aim for a center-ball hit (with no sidespin) resulting in no compensation for CB deflection (e.g., for shots where swerve is expected to cancel the effects of squirt and throw, resulting in no net CB deflection, or where the amount of resulting pocket cheat is acceptable).
Corollary - Lines that are not parallel will intersect at some point
Divergent English - where the cue placement is not parallel to the center ball aim line. The line the cue is on will cross the center ball aim line on the player side of the cue ball.
BHE - a type of divergent english where the cue line diverges from the current ball aim line at the bridge
FHE - a type of divergent english where the cue line diverges from the current aim line at the grip location
Convergent English - where the cue placement is not parallel to the center ball aim line. This line converges with the current aim line on the other side of the cue ball from the player aim position.
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