An object is in motion when its distance from another object is changing. A reference point is a fixed place that you compare an object that is in motion to. A object is in motion if it changes position relative to a reference point. Speed is the distance an object travels in one unit of time. If an object moves at a constant speed it can be determined by dividing the distance it travels by the time taken to get to a specified point. When both the speed of an object an object and the direction the object is traveling in are stated than velocity is being described.