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Help with tension physics

  1. Aug 31, 2005 #1
    A pulley is attached to the ceiling. Spring scale A is attached to the wall and a rope runs horizontally form it and over the pulley. The same rope is then attached to a spring scale B. On the other side of scale B hangs a 120 N weight. What are the readings of the two scales A and B? The weights of the scales are negligible.

    please help
  2. jcsd
  3. Aug 31, 2005 #2


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    I don't see why the scale readings shouldn't be the same. The pulley is considered mass-less correct?
  4. Aug 31, 2005 #3
    Well... If I have pictured it correctly then they would both read 120N

    As there are in series so to speak. If they were in a parallel arrangement then it would be 60N each (that is if there were 2 strings holding from the ceiling).

    I think the pulley is irrelevant and you could imagine the system just hanging from the ceiling.
  5. Aug 31, 2005 #4


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    Also, the question neglects friction in the pulley.

    This is a statics problem and the question becomes, what can you say about the tension in the string? What is the effect of the pulley?
  6. Aug 31, 2005 #5
    thanks thats what i thought also
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