A tennis ball is projected toward a smooth surface with spee
     A tennis ball is projected toward a smooth surface with speed v as shown. Determine the rebound angle and the final speed v\'  The coefficient of restitution is 0.6. 
  
  Solution
Coefficient of Restitution = Rebound Speed/Original Speed
0.6 = v\'/v
v\' = 0.6v
Hence the rebound speed or final speed is equal to 0.6v
Coefficient of restitution = 0.6 = tan(i)/tan(r)
0.6 = tan(45)/tan(r)
tan(r) = 1.6667
r = 59.03 degrees

