Question

Angle of rebounce given coefficient of restitution

Answer 1

If the ball slides throughout the bounce then F/N = coefficient of sliding friction. But that happens only if the ball is incident at a glancing angle to the surface, typically about 20 degrees or less. At larger angles of incidence, the bottom of the ball will come to a stop before the ball bounces, and grip the surface, in which case static friction acts on the ball. F is then determined by elastic distortion of the ball in a direction parallel to the surface, and acts as a shear force. F can even reverse direction during the bounce