Redirect at base of tree- easier pull?

i think the simple answer is that the first scenario as pictured (with a man positioned as he is) will be easier due only to two things:
-the angle enables the man to use gravity in his favor, putting his weight into the pull a lot more efficiently than he could if he was pulling horizontally as he is in the second scenario.
-the second factor is the greater friction, not just because of the extra pulley but also because the load on the top pulley is considerably greater in the second scenario due to the more acute angle.
 
Perhaps if we take the boy out of the #3 scenario as well as it's pairallel scenario/choice D ; and in his place, put a come along. Then maybe it is easier to conceptualize, that tightening CAL tightens 2 legs of line to load. Whereby, the force generated gives up distance, as 2 legs of line are tightened, but CAL is only attached to 1.....

That is a 2/1. Furthermore, hang a 100# weight from the upper connection, and place a scale inline, on same leg as CAL. Tighten come-a-long up to 40# on the one leg, that shares it's tension with the other leg; thereby givng up distance. That should be the 100# weight of boy + his 40# dual arm pull; forgivng come-a-long weight of curse.

Note, that if CAL was hooked straight to the anchor, then, tightening up the CAL only tightens 1 leg of line pull to to target; for a 1:1. But, when CAL pulls on 1 leg, to tighten 2; gives 2/1. Allowing the E&O to pull on the target too, is like allowing 2 men to pull on target instead of 1. It is like instead of running a human chain to anchor to brace and pull hard in series, they split a line and each reach the anchor, and each pull seperately.

Orrrrrrrrrrrrrrrrrrr sometin'like that!

Fergive me, i all ways calculate by feel, visualizing self in scenario, perhaps taking out humane elemeant gives better view to others. Allowing a step back to view, not distracked by feel.

/forum/images/graemlins/crazy.gif




EDIT: See drawing #4 in Force Relationships Thread.

More Power to Ya!
-KC
 
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