Finding the Coordinates of Point A in a Force Equilibrium System

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The problem involves finding the coordinates of point A in a force equilibrium system, where the sum of forces in both the x and y directions equals zero. The system includes a downward weight W and two equal tensions T in the ropes. Key considerations include the distance ε between the weight and its pulley, and the angles α and β of the ropes with the horizontal. By resolving the tensions into components, it is determined that the angles are equal (α = β = 30°), leading to the equations for x and y coordinates based on trigonometric relationships. This approach effectively addresses the equilibrium conditions to solve for point A's coordinates.
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Homework Statement


The system is in equilibrium. What are the coordinates of point A?
(see attached image)


Homework Equations


ƩF_y = 0
ƩF_x = 0

The Attempt at a Solution


The sum of forces in the x and y directions is zero since the system is in equilibrium. At point A, I also know that there is a weight W directed downwards, and each of the two tensions in the ropes T are equal in magnitude.

I was told that this "proof" problem required consideration of the distance between the weight on the left and its pulley (call it ε), and also the two angles (α and β) between each of the two ropes at point A with the horizontal.

Although I was given these hints, I still can't figure out where to start in the problem. Can anyone help me out here? Thanks!
 

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Actually all the tension of the strings are equal.
Using these values, you can find the angles by resolving the components.
 
Nivlac2425 said:

Homework Statement


The system is in equilibrium. What are the coordinates of point A?
(see attached image)


Homework Equations


ƩF_y = 0
ƩF_x = 0

The Attempt at a Solution


The sum of forces in the x and y directions is zero since the system is in equilibrium. At point A, I also know that there is a weight W directed downwards, and each of the two tensions in the ropes T are equal in magnitude.

I was told that this "proof" problem required consideration of the distance between the weight on the left and its pulley (call it ε), and also the two angles (α and β) between each of the two ropes at point A with the horizontal.

Although I was given these hints, I still can't figure out where to start in the problem. Can anyone help me out here? Thanks!
attachment.php?attachmentid=45987&d=1333848177.jpg


What is the tension in each of the three ropes ?
 
SammyS said:
What is the tension in each of the three ropes ?

I believe the tensions are equal and they are all equal to W
 
Nivlac2425 said:
I believe the tensions are equal and they are all equal to W
Correct.

What does that tell you about the angles made by the three ropes at point A ?
 
SammyS said:
Correct.

What does that tell you about the angles made by the three ropes at point A ?

So if I resolve the tensions into their components, and realize that the sum of forces in x and y are both equal to zero, I get the following relations:

sin(α) + sin(β) = 1

cos(α)=cos(β)

This tells me that the angles must be equal, and that α = β = 30°

And since: tan(α) = (h+y)/(b-x) and tan(β) = y/x,

I get x = (1/2)[b - hcot(30°)] and y = (1/2)[btan(30°) - h]

Is this the correct way to think about the problem?
 
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