Conservation of Mass in Collision

The conservation of mass in inertial reference frame is a property of the conservation law of momentum. The inelastic collision between two identical objects shows that the total momentum is zero in the COM frame (center of mass). In another inertial reference frame, the rest frame of one object before collision, the total momentum before the collision is equal to the total momentum after the collision. This conservation of momentum shows that the mass of an object is also conserved in all inertial reference frames. The mass of a moving object is independent of its velocity.