Cables, pulleys, 2 weights

  • #1
DylanMurfly
3
0
Homework Statement
I've been struggling with this question for a while now, and for the life of me i cant see what i'm missing, the picture is in the solution attempt along with the equations i've been using. Any assistance would be amazing. Find: Tension AB and Angle a
Relevant Equations
W1 = 330g
W2 = 440g
1713386600869.png

Fx = 0 = ABcos(a)+BCcos(b)-BDcos(30)
Fy = 0 = ABsin(a)+BCsin(b)-BDsin(30)

==

Fx = 0 = ABcos(a) + 3.2737cos(b) - 3.738
Fy = 0 = ABsin(a) + 3.237sin(b) - 2.158

But i cant find a third equation to use. I've tried a+b = 90 but that produced a number of errors. Thank you.
Edit: angle b is the angle string CB makes with horizontal
 
Last edited:
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  • #2
Please post the question that the problem asks. What are you looking for? The homework statement must be as was given to you.
 
  • #3
kuruman said:
Please post the question that the problem asks. What are you looking for? The homework statement must be as was given to you.
updated, sorry about that
 
  • #4
Finding the tension AB is easy. You are missing that when the sum of N vectors is zero and you draw the vector addition diagram, the ensuing shape is a closed polygon with N sides. Apply this idea here.
 
  • #5
Thank you sir, got it all fixed up now, didn't even think to go about it that way, earlier response was a brain fart as its quite early in the morning and i haven't had a coffee yet.
 

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