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Cable friction and tension problem

  1. Nov 14, 2006 #1
    Read please example 2 of http://cnx.org/content/m14060/latest/ .



    On picture 2 there are those two tension labeled by T which are equal. Why equal?

    And shouldn't they exert just torque? I know we are considering the pulley to be massless, so no torques. So is it correct to consider those two tensions applied at the center of mass of the pulley?

    Thanks in advance for your clarification. :smile:
  2. jcsd
  3. Nov 14, 2006 #2
    The cable has to have the same T, because that is the nature of strings and cable. It is irrelevant where you applie them. The magnitude and direction matter. There is torque on the pulley, but they cancel out.
  4. Nov 14, 2006 #3
    That is because thay are the same cable and there is supposedly nor friction in the system. You might, for an instant initially get tension which is different from the other but you can imagine that the tension is 'transferred' along the cable until they are equal.
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