🏀 Ball Pressure and Bounce Height: Spring-Damper Contact from Inflation Pressure and the e-Squared Rebound Law

A ball is dropped on a rigid floor; its internal pressure sets the contact stiffness k = 2 pi r p, a calibrated damper sets the energy loss, and the first rebound follows h1/h0 = e^2 from the closed-form restitution. Sweep the inflation pressure and compare the simulated rebound with the formula and the commonly quoted football rebound band.