# Coefficient of restitution belongs to kinetics and not to kinematics?Reason

The Coefficient of restitution is defined as $$e=\frac{v_2-v_1}{u_1-u_2}$$ $$v_2\to \text{final velocity body 2}$$ $$v_1\to \text{final vel of body 1}$$ $$u_1\to\text{initial vel of body 1}$$ $$u_2\to\text{initial vel of body 2}$$ It was a question in an interview. The question is why is this equation considered in kinetics and not kinematics.

this equation does not contain any mass term but still it is considered in kinetics.Why?

• Kinetics as to kinetic theory of gases, I hope? – SchrodingersCat Nov 26 '15 at 13:18
• kinetics of rigid bodies – Vinay5forPrime Nov 26 '15 at 13:21
• It was in the college the professor asked – Vinay5forPrime Nov 26 '15 at 14:38