# Determining the forces in three cables.

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1. Mar 11, 2015

### cavalieregi

1. The problem statement, all variables and given/known data

2. Relevant equations

3. The attempt at a solution
1. I first found the angles each cable made with the pillar.
2. With these angles I found the components of the forces in the x and y direction.
3. So ∑Fx and ∑Fy were found.
4. Then using these values I equated that
$F = \sqrt(F_x ^2 + F_y ^2)$
5. The from here I subbed Fb and Fc = Fa and that F = 200kN Then rearranging to get Fa I got Fa = 112.36N however it should be 68.4kN.

I am unsure where I have gone wrong. Note vectors are not to be used to solve problem i.e using i, j and k components.

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2. Mar 11, 2015

### TSny

Your approach looks good. You must be making an error somewhere in the calculation. I get 68.2 kN for the answer.

3. Mar 11, 2015

### cavalieregi

So could you give me a rough outline of your method.

4. Mar 11, 2015

### cavalieregi

Don't worry I worked it out.