Re: ROTATION

[David Bowman <David_Bowman@GEORGETOWNCOLLEGE.EDU>]

Regarding:
> If a long thin rod is rotating about one end is it also rotating about
> its center?  If so, what is the relationship between its angular
> velocity about its end and its rotational velocity about its center?

If the rod is pivoting about one end so that the axis of rotation is
perpendicular to the rod then this motion is equivalent to the
superposition of a rotational motion about the center *and* a
revolution of the center about the pivot point.  The angular velocity
of rotation about the end, the angular velocity of rotation about the
center and the angular velocity of the revolution of the center are all
the same (with the sense of the direction of the circular motion being
the same for all 3 motions as well).  The radius of the circle for the
revolution of the center is 1/2 of the length of the rod.

David Bowman
David_Bowman@georgetowncollege.edu