Consider a point on the edge of a spinning disc following a parabolic path during a discus throw event. The point takes a complex path even when the disc continues to move in a parabolic path, whereas the center of the disc follows the same path as that of the disc. This point is called the center of mass rcm of the disc. The concept of center of mass helps to illustrate the object as a point mass. During the motion, the object's center of mass moves such that the total mass is condensed in a single point. Consider several particles of masses mi with respective position vectors ri. Then, the position vector for the center of mass is written as the summation of mass times position vector divided by the total mass of all the particles. The coordinates of the center of mass can be expressed as the summation of the product of mass and the individual coordinates of the position vector divided by the total mass.