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Homework Help: Static equilibrium; pulley and inclined plane problem.

  1. Jul 3, 2015 #1
    1. The problem statement, all variables and given/known data
    What weight WB will cause the system to be in equilibrium? Neglect all friction, and state any other assumptions.
    2. Relevant equations

    3. The attempt at a solution
    I cant figure out what im doing wrong with these pully problems, I tried putting in resultant forces at pully A, but that just added another variable.

  2. jcsd
  3. Jul 3, 2015 #2
    You should check the Wb is Tb or ___ ?
  4. Jul 3, 2015 #3
    I did a redo of the tensions this time starting from A going to B, im still missing something though. solving for weight at B i got 8.72lb (on the right side of my paper)
  5. Jul 3, 2015 #4
    It seems correct to me.
  6. Jul 3, 2015 #5
    Yea, but im still missing something, its not the correct answer.
  7. Jul 3, 2015 #6
    Oh, find the F again you will see the wrong :) 79,5 N or kg ?
  8. Jul 3, 2015 #7
    If the weight of block A is 175 lb that is equal to 79.5N
  9. Jul 3, 2015 #8
    ok i got, my mistake was trying to convert from english to standard, i should of just left it in english. thanks thypon.
  10. Jul 3, 2015 #9
    No, 1lb is equal to 0,453 kg, so 175lb =79,27 kg
    N means kg*m/(s^2)
  11. Jul 3, 2015 #10
    i got confused because 175 lb of weight = 175 lb mass.
  12. Jul 3, 2015 #11
    Is it okay now ?
  13. Jul 3, 2015 #12
    yea its correct now. thanks
  14. Jan 25, 2017 #13
    Why is the tension T/2?
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