(Conservation of momentum) The momentum of an isolated system remains always constant, regardless of how the parts that make up the system may interact with one another. In one dimension, the center o...(Conservation of momentum) The momentum of an isolated system remains always constant, regardless of how the parts that make up the system may interact with one another. In one dimension, the center of mass of a system of particles is a mathematical point whose \(x\) coordinate is given by Equation (3.3.1) above. (In more dimensions, just change the \(x\)’s in Equation (3.3.1) to \(y\) and \(z\) to get \(y_{cm}\) and \(z_{cm}\).)