Uniform and non-uniform circular motion
Circular motion is the movement of an object on a circular path. This means that the movement of the object traces the arc of a circle (as opposed to following an arbitrary curved path).
Circular motion can be classified into uniform and non-uniform circular motion:
An object undergoing uniform circular motion moves with a constant speed (only the direction changes).
An object undergoing non-uniform circular motion moves with varying speed.
Unless otherwise mentioned, it is assumed (by convention) that objects undergoing circular motion do so uniformly (i.e. with constant speed).