Dan-cat wrote:Isn't the idea when you apply side to go around a ball in the way to simply bend it slightly, and then when it returns to the original line it can pot the ball?
Not really, no. Straightening a pot up with side is a different thing to bending/swerving round an obstacle ball in order to meet a potting angle.
Usually in the first instance (straightening up a pot using side) the cue ball and object ball are pretty close, let’s say a red near the pink spot into the corner with the white a foot away. In this case the shot is to use side transfer. A player will cue the shot with no real extra elevation to the butt of the cue in comparison to a plain ball shot; the object here is not to bend the white (there’s not enough distance to gauge a swerve accurately) but to transfer side. Left on the white creates right on the object ball. The reason this imparted left hand side changes the angle of the object ball is that the inertia, mass and friction coefficient of two balls is equal. Where a cushion will not ‘react’ to impact with a ball with say right hand side on (much larger mass, inertia etc than another ball) an object ball will react somewhat equally to the cue ball, but in opposing direction (again, 3rd law). Imagine the widened angle of a ball hitting a cushion with right hand side. Now take the inverse of that widened trajectory and apply it to the object ball that’s struck by a cueball with right hand side on it. It squeezes to the left.
A swerve is different. In that case you’re actually manipulating the line of the white in order to create a potting angle that isn’t possible in a dead straight line. The caveat to this is that because a swerve is also an application of spin, to a lesser degree spin transfer will also occur. This degree is determined by how much spin has remained on the white between the stroke and the impact with the object ball. For this reason - distance - you’ll find close pots are better candidates for simple spin transfer, and longer pots are better candidates for a swerve.