What is rolling and what is its condition to take place?

Rolling is defined for circular bodies only it is the combination of rotational and translational motion the contribution of both the parts is equal'

If abody is rolling that is it is translating with a velocity v and is rotating with an angular velocity wif the radius of the body is r then as soon as the condition is met that v = rw rolling starts. so this is the desired condition for rolling

                                                                                                  v = rw.