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(Doug Miller) wrote in message . com...
In article , (The Other Harry) wrote:
[On Wed, 10 Mar 2004 14:08:41 GMT, "Michael Daly"
wrote:]

If you don't beleive it, get a spring balance and test it.
You can use a light rope and something weighing only 10lb
or so.

I might just do that.

You'll be surprised. I was -- when I read the first post this morning that
stated it would be 80 lbs, my first thought was "what a bunch of crap". But
the poster's reasoning seemed valid to me. So I tried it, using a reasonably
good spring balance, a toolbox, and a rope. The toolbox, just hanging from the
spring balance, weighed 28 lbs. Then I tied the rope to the toolbox handle,
passed it through the hook on the balance, stood on one end of the rope, and
lifted the toolbox by the balance: 55 lbs.

You bet. Another way of thinking about it: instead of standing on the
other end, what if you hung another 28 lb toolbox on it as a
counterbalance. Obviously then the balance will show the combined
weight. Well, the balance doesn't care whether it's tied off or
holding a counterweight, it sees 28 lb tension in each of the two legs
of rope.

Now suppose you'd paid an engineer to design a hook in the middle of
your ballroom ceiling to hold a quarter-ton chandelier, and then
decided later to hang it with a rope over a pulley ...

Chip C