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PUlleys,,,,,

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vayntraubinator

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Can someone please explain them and make them easy?

Im just so confused as to whats going on...

http://mcat-review.org/force-motion-gravitation.php#analysis-pulley-systems

http://en.wikipedia.org/wiki/Pulley

399px-Pulley2.svg.png


Thanks :)
 

kkentm

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theres no real explanation for it, you just need to develop an intuition of pulley systems where you can visually assess the tension forces. in this case the weight of the mass is evenly distributed over the pulley system in such a way that the tension at the 3 points indicated are all W/3 (upwards)
 

tn4596

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it is pretty simple dude...
how many rope is attacked to the weight? 3..therefore the tension is mg/3. Do not pay attention to how they are set up, just find out how many rope is attached.
 

costales

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There is only one rope used. Since it's the same rope, the tension is the same throughout. Three segments of the rope provide an upward force to counter W, so each segment must have a tension of W/3 to add up to W.
 

Majik

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It might help in realizing that for a rope, tension is the same everywhere along it. Each time the rope pulls upwards, there's a force/tension applied in the upward direction. This upward force is countered by the weight of the object. Assuming you're pulling at constant velocity, which is the case most of the time, then the net force = 0N.

If Fnet = 0, then weight = Tension 1 + Tension 2 + Tension 3

Earlier I said these tensions are equal, so instead I should say that:

Weight = 3T (where T = tension in rope).
 

vayntraubinator

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Thanks, I think I've figured it out guys. Guess I was just confused about when the rope your pulling actually accounts for a rope that divides the total force.
 
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