As I recall, this was done in an old PSSC film much as you have
described. Their tape length was fairly long - they used a two story
room as I recall. They also attached a mirror to the meter stick and
bounced a light beam off the mirror to a wall some distance away. This
would be much easier today with laser pointers. The period was very
long - on the order of minutes if I recall. They took the difference in
the center of oscillations in order to determine the twist provided by
the shifting masses. The weights never came to rest (equilibrium).
Glenn Malin
University HS
Irvine, CA
thomaspfeiffer2002@YAHOO.COM 11/12/02 09:00AM >>>
Greetings phys-eders:
I am attempting to set up an experiment similar to
what Cavendish did when he "weighed the earth".
I'm using two joint compound buckets filled with sand
as the larger masses. I have a meterstick horizontally
oriented with bottles of sand on each end. This is
suspended from the ceiling with video tape.
|
|
/\
/ \
/ \
________
0 0
OO OO
(In front) (In back)
I'm finding that it takes an incredibly long time for
the suspended meterstick to find its equilibrium
position. Once it does, I'll move the buckets in
closer to the bottles of sand and see if I can detect
any torque on the meterstick.
My questions are:
1)Do you think the incredibly small Fg would produce
any effect?
2)Have any of you tried this before? If you did, how
did it work?
3) Any suggestions?
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This posting is the position of the writer, not that of SUNY-BSC, NAU
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This posting is the position of the writer, not that of SUNY-BSC, NAU or the AAPT.