Re: ROTATION

["Spagna Jr., George" <gspagna@RMC.EDU>]

David Abineri asks:

> -----Original Message-----
> From: David Abineri [mailto:dabineri@CHOICE.NET]
> Sent: Thursday, September 07, 2000 7:09 AM

> If a long thin rod is rotating about one end is it also rotating about
> its center?

Yes!

> If so, what is the relationship between its angular
> velocity about its end and its rotational velocity about its center?

The angular velocity is the same for both reference frames.  Think of a
wheel which rolls without slipping as the superposition of two motions: the
center of the wheel is in translational motion at constant velocity. The
rest of the wheel is in rotation about the center.  In the case of your rod
example, the center of the wheel is in uniform circular motion.  The rod
itself is in "pure" rotation at the same angular frequency.

******************************************************
"With a little more deliberation in the choice of
       their pursuits, all men would perhaps
become essentially students and observers ..."
                  - Henry David Thoreau
******************************************************
George Spagna
Department of Physics
Randolph-Macon College
P.O. Box 5005
Ashland, VA 23005-5505
phone: (804) 752-7344     FAX (804) 752-4724
e-mail: gspagna@rmc.edu
http://www.rmc.edu/~gspagna/