Impact of a cue with a billiard ball.

This article focuses on experimental investigations into how the speed and spin of a billiard ball vary with the vertical impact point of a cue strike relative to the ball's center. Using a ball struck at different heights above and below its center, the study measures translational and rotational velocities and compares these results with theoretical impact models incorporating normal and tangential forces. Findings indicate that the ball's outgoing speed is highest when struck near its center, while spin increases linearly with impact height, reaching a maximum near the top or bottom before cue tip slippage (miscue) occurs due to insufficient static friction. The study also refines the concept of the center of percussion, showing it aligns closely with the slip point rather than the classical theoretical prediction, and highlights the role of friction between the cue tip and ball in determining spin and speed outcomes.