Date: Thu, 16 Nov 2000 12:00:33 -0600

Author: "Defayette, Thomas F."

Subject: RE: CM Demo


A very easy demo for static equilibrium is a small piece of wood about 4"
long (cut 4" off old meter stick). Saw a slot on the long side about 1"
long, approx 45 degrees towards the middle of the piece of wood. Take belt
off your pants / slacks (be careful pants do not fall to ground!). Place
belt in slot and let the both ends of the belt hang off the side of the
piece of wood. Balance the piece of wood off a table's edge or your finger.
The combination of torques and normal forces allows the wood to mysteriously
hang off the edge of table. Only a small portion of the wood needs to be on
the edge of the table. The belt and the rest of the wood hangs off the table
(or your finger) freely.

-----Original Message-----
From: Stephen Skinner []
Sent: Thursday, November 16, 2000 9:12 AM

To All,

Does anyone have a really good center of mass toy? Something that show
static equilibrium when the object looks like it should fall over. A
professor was trying to describe to me one of his kid's toys; a man standing
on a pedestal holding a curved object. The man was standing in such a way
that it looks like he should topple over, but because of the curved object
the man's center of mass was above the pedestal's top. Any ideas?

Stephen R. Skinner
University of Arkansas
Instructional Laboratory Curator
PHYS 246