Cables, pulleys, 2 weights

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Homework Help Overview

The discussion revolves around a problem involving cables, pulleys, and two weights, focusing on the equilibrium of forces in a system. The original poster presents equations related to the forces in the x and y directions but struggles to find a third equation necessary for solving the problem.

Discussion Character

  • Exploratory, Assumption checking, Problem interpretation

Approaches and Questions Raised

  • The original poster attempts to use trigonometric equations to express the forces but indicates difficulty in deriving a third equation. Some participants question the clarity of the problem statement and request the original homework question for better context.

Discussion Status

Participants are actively engaging with the problem, with one suggesting a geometric approach involving vector addition to visualize the forces. There is acknowledgment of the original poster's confusion, and a sense of progress is noted as they express understanding after receiving feedback.

Contextual Notes

The original poster mentions an angle related to the string's orientation and notes a previous misunderstanding in their approach, indicating a need for clarity in the problem setup.

DylanMurfly
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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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Please post the question that the problem asks. What are you looking for? The homework statement must be as was given to you.
 
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
 
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.
 
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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