Because this is a computer model rather than a real object, we can also show the center of mass of the object. It is the larger white spot. What we will do next is develop the tools necessary to predict the future of an object undergoing this sort of motion. A different set of variables are used to describe rotation. The displacement in translation was measured along the coordinate axes, or as a distance and direction.
Angular displacement is evidently a scalar quantity since one number completely defines it.
If the reference line is the x axis, the angular displacement is the angular position. A radian is the ratio or the length of the arc cut by an angle, to the length of the radius of that arc. See the Angular Displacement display for an illustration. Since it is the ratio of two lengths, the radian is unitless. We also have measures in rotation analogous to velocity and acceleration.