English refers to the spin imparted on the cue ball, causing it to deviate from a straight path. There are three types of English:
First published in the mid-1990s, the book has retained a cult following because physics does not age. While cue technology has evolved, the laws of motion governing a 2.25-inch sphere on felt have remained constant for centuries. Science of Pocket Billiards download pdf
The friction between the ball and the table is described by the coefficient of friction (μ). The value of μ depends on the table's surface, the ball's material, and the speed of the ball. A higher μ value results in more friction, causing the ball to slow down and change direction more quickly. English refers to the spin imparted on the