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Mechanics

Angular Momentum of a Point Mass

The angular momentum, L of a point mass is given by L = Iw and the moment of inertia of a point mass is I = mrČ

so, we have

L = (mrČ)w

and, as v = rw we can write

L = (mv)r

Which means that the angular momentum of a point mass is equal to its linear momentum multiplied by its distance from the point considered.

Notice that we can therefore calculate the angular momentum of a body about any point (point O in the diagram above), even if the body is not moving in a circular path.

© David Hoult 2008