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Forces on a Pulley

  1. Sep 16, 2006 #1
    i am confused about where forces act on a pulley.
    IF the pulling forces act on the edge or bottom?
    Also, I don't know why when we pull one end of the rope, we apply an upward force on the pulley and on the other hand the force, tention, act on another end also. Is the Force routed like a "parallel circuit?

    You may refer to this image:
    Last edited: Sep 16, 2006
  2. jcsd
  3. Sep 17, 2006 #2
    Like a centripetal acceleration.. I hearby assert without proof that the force on any portion of the pulley is simply proportional in magnitude to the curvature of the rope and the tension in the rope (and directed normal to the pulley surface). In your diagram, that means little arows evenly distributed round half the pulley circumference, all pointing towards the center (with equal length), in addition to the force F acting on the center of the pulley.
  4. Sep 18, 2006 #3

    So u mean the force is acting on the surface of contact. But, how can a force separately act on two object with magnitude the same as the apply one?
  5. Sep 18, 2006 #4


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    The contact force is an internal force, and it is irrelevant in pulley problems.
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