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Pulley with an angle

  1. Apr 24, 2014 #1
    Hello everybody

    Im trying to calculate the tension in wire (se attached image). the wire is wrapped around a pulley and combined in the end at which you pull with 50 kN. As far as I understand, if youdon´t have this angle so that that the wire ends follow the red dotted line then one can just devide the pulling strength by a factor of 2. But how does this angle influence?

    Best regards

    Attached Files:

  2. jcsd
  3. Apr 24, 2014 #2
    decompose the tension force on the string into two components. One of the components ought to be parallel to the red line while the other component will be perpendicular
  4. Apr 25, 2014 #3
    If the wire is bend a certain angle A, then the tension in the wire would be F*cos(A)?, then this would make the tension in the wire smaller - I have done this experiment in real life and experienced a smaller force was nessecary in order to brake the wire compared to a normal pull in the wire.
    Am I not understanding you rigth?
  5. Apr 25, 2014 #4


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    Staff: Mentor

    It's the other way around - the tension in the wire is greater not smaller when there's an angle. You may have multiplied somewhere when you should have divided? Show your work and someone here will spot the problem.
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