Harry K wrote:
snip Harry's trying to claim he isn't lying about his test

Sorry for you. Here is the only one I found that comes close. It is
some better than Tom's. Note that I have done the research, you
haven't.

http://science.howstuffworks.com/pulley.htm

Best I could find on the net. Do you see the force vector arrows in
the diagram? They show 100 lbs down force on the right, 100 lbs up
force on the right and another 100 lbs down force on the left. Notice
the two 100 lbs down? Yep, that would mean 200 lbs on the hook.

But wait a minute. There is one 100 lbs -up- force. That cancels one
of the downs leaving

Count all the forces Harry. There's _three_ 100 lb down forces, and one
100 lb up force. That's two hundred pounds down, not that you care.

But thier diagram is fubar.

100 lbs remaining acting on the weight and the hook. Just as I said
and just as my tests show.

Well, just to humor the net kook, I did the test. As I expected the load
is twice as high as the weight.

Now, let's try a more novel approach that may get through to you.

With this set up:

|
+
/|\
| |
|\_/|
| |
| |
A B

Even you will agree that load A must equal load B if the pully is to
remain in balance. Also, you'l not that for every inch you move B down, A
will go up one inch. If you read your cite you'll see the force-distance
trade off. Essentially if the distances moved are one to one, then the
loads are one to one. If, as in the second picture on the how stuff works
site, the pullys are arranged such that the load moves only half the
distance the rope is pulled, then the pull on the rope must also be half
the load. Agreed?


OK, now. The A-B pully I diagramed above is also a scale of sorts. We
know that A must equal B.

Now, let's take B and attach another pully arangement just like the one
we've used befo

|
+
/|\
| |
|\_/|
| |
| |
A B
|
+
/|\
| |
|\_/|
| |
| |
C D

Pully CD is now the same set up with the planter. The load at B is the
load we've been discussing. The load at A will be the answer. OK, now, D
is fixed: tied off to the ground. We move C down one inch.

Q1: How far does B move?
A1: it moves down one half inch.

Q2: How far does A move then?
A2: it moves up one half inch.

Q3: What is the ratio of distances moved from C to A?
A3: Two to One.

Since we've established that the ratio of distances moved governs the
ratio of the loads, then it must be that the load at A equals twice the
load at C. Since the load at B must equal the load at A we get the load
at B equal to twice the load at C.

Just like everyone has been trying to tell you.



John
--
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