The loss of kinetic energy during inelastic impact, is given by (where m1 = Mass of the first body, m2 = Mass of the second body, and u1 and u2 = Velocities of the first and second bodies respectively.)
[m₁ m₂/2(m₁ + m₂)] (u₁ - u₂)²
[2(m₁ + m₂)/m₁ m₂] (u₁ - u₂)²
[m₁ m₂/2(m₁ + m₂)] (u₁² - u₂²)
[2(m₁ + m₂)/m₁ m₂] (u₁² - u₂²)
