Recall (§B.3) that the momentum of a mass traveling with velocity in a straight line is given by
while the angular momentum of a point-mass rotating along a circle of radius at rad/s is given by
where . The tangential speed of the mass along the circle of radius is given by
Expressing the angular momentum in terms of gives
Linear momentum can be viewed as a renormalized special case of angular momentum in which the radius of rotation goes to infinity.