Help with tension physics

  • #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
 

Answers and Replies

  • #2
mezarashi
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I don't see why the scale readings shouldn't be the same. The pulley is considered mass-less correct?
 
  • #3
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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.
 
  • #4
Astronuc
Staff Emeritus
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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?
 
  • #5
thanks thats what i thought also
 

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