Motion state definition
Motion state refers to the state of the motion speed of an object relative to a certain reference frame when the object is in mechanical motion. The contents of the motion state include: the size of the motion speed of the object (the amount of change of the object's position vector per unit time (dr/dt), that is, the displacement of the object per unit time) and the direction of the object's motion speed. Stillness or movement also falls within its scope.