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From: bnp@ihldt.UUCP
Newsgroups: net.physics
Subject: Re: Hourglass (spoiler)
Message-ID: <2026@ihldt.UUCP>
Date: Mon, 3-Oct-83 17:57:09 EDT
Article-I.D.: ihldt.2026
Posted: Mon Oct  3 17:57:09 1983
Date-Received: Tue, 4-Oct-83 02:43:27 EDT
References: <679@ihuxr.UUCP>
Organization: BTL Naperville, Il.
Lines: 20


	I think I have seen a problem similiar to this one;  in high
school physics our teacher used to give "demonstration problems" during
exams.  When there was about 15 minutes left in the class period, he
would get everyone's attention, perform a demonstration similiar to
(but always a little more difficult than) one we had seen and explained
in class.  As the final question on the test, we would have to
qualitatively explain what happened in the demonstration.

	Anyway... One of these demonstrations consisted of a balance
with a yo-yo tied to one side, and static weights equalling the mass
of the yo-yo on the other side.  He then would wind the yo-yo string
and released it.  As it fell and then rose again, the balance would
show first one side as "heavier", and then the other.  As I recall, the
balance "switched" as the yo-yo reached the bottom of its string.

		Still a little confused....,
			Bruce Peters
			BTL - Naperville, Ill.
			...!ihnp4!ihldt!bnp