‘u₁’ and ‘u₂’ are the velocities of approach of two moving bodies in the same direction and their corresponding velocities of separation are ‘v₁’ and ‘v₂’. As per Newton's law of collision of elastic bodies, the coefficient of restitution (e) is given by

• A. e = v₁ - v₂/u₂ + u₁
• B. e = v₁ - v₂/u₂ - u₁
• C. e = u₂ - u₁/v₁ - v₂
• D. e = v₂ - v₁/u₁ - u₂

Answer: (D)