Modeling the Effects of Velocity, Spin, Frictional Coefficient, and   Impact Angle on Deflection Angle in Near-elastic Collisions of Phenolic Resin   Spheres
  A simple model is outlined to describe the collision of cast phenol-formaldehyde resin spheres such as the balls used in the parlor game of pocket billiards, based in part on the famous analysis of elastic collisions developed by Heinrich Hertz over 100 years ago. The analysis treats the normal and tangential components of the initial sphere's velocity independently as it collides with a stationary identical second sphere. The collective effects of these and other parameters on the trajectory of the second sphere are provided in the conclusions. 
S.C. Crown