Akash Malhotra posted
Real world application, COR –> Bounce produced by pitch, for both spinners & seamers; Contact time –> grip provided by pitch, mainly for spinners

Assuming cricket ball (leather ball) to be a sphere and cricket pitch (hardened soil) to be a flat. 
1. Would it be appropriate to assume cricket pitch as elastic-plastic flat and cricket ball as elastic-perfectly plastic sphere for modelling purposes? 
2. Does there exist any relationship (empirical or physical), relating coefficient of restitution and contact time between a sphere and a flat to their respective material properties and incident velocity.