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Re: FOX Show



At 3:27 PM -0500 11/10/00, Michael Edmiston, you wrote about Re: FOX Show:


I have seen several textbooks used
in middle-school science that draw pictures of this, but fail to count the
odd cable (the one attached to the bottom pulley) as a supporting cable.
Some books even define the mechanical advantage as "twice the number of
times the cable passes through the lower pulley." Of course that "rule" is
only correct if the cable does not attach to the lower pulley, and from what
I have seen "in the field" it is just as likely to attach to the lower one
as to the upper one.

I like the example of a person standing on a platform
attached to one end of the rope.

The person pulls down on the rope that has passed up thru a
SINGLE pulley which is rigidly attached to the 'ceiling'.




For some reason, few middle-school textbooks give the
simple rule of just counting the number of cables that run to the lower
pulley.

Doesn't Leigh have a glorious pulley arrangement that does NOT follow
the 'count the ropes' method???

-. .-. .-. .-. .-. .-. .-. .-. .-. .-
\ / \ / \ N / \ C / \ S / \ S / \ M / \ / \ /
`-' `-' `-' `-' `-' `-' `-' `-' `-'
Chuck Britton Education is what is left when
britton@ncssm.edu you have forgotten everything
North Carolina School of Science & Math you learned in school.
(919) 286-3366 x224 Albert Einstein, 1936