(adsbygoogle = window.adsbygoogle || []).push({}); 1. The problem statement, all variables and given/known data

Ok, I've got three cables all pointing in a downward direction towards the orgin. They all connect at the orgin, onto a 750lb weight. Determine the tensions in A,B,C.

I'm going to put these into (x,y,z) form, so you get the picture.

A = (4,-2,5)

B = (-3,-3,6)

C = (-4,3,4)

2. Relevant equations

3. The attempt at a solution

Ok, I've tried this...not sure if its right, but seems right to me. And...if so, I'm stuck at the point of how to solve the 3 equations and 3 unknowns. I can't remember how to do that. Ok here goes...I hope this isn't complicated.

R = sum(F) = Ta + Tb + Tc = 0

Ta = Ta(4i - 2j +5k/sqrt(45))

Tb = Tb(-3i - 3j +6k/sqrt(54))

Tc = Tc(-4i + 3j +4k/sqrt(41))

Skip a step here.....

R = (0.5963Ta - 0.4082Tb - 0.6247)i + (-0.2981Ta - 0.4082Tb + 0.4685Tc)j + (0.7454Ta + 0.8165Tb +0.6247Tc)k

Sum(Fx) = 0.5963Ta - 0.4082Tb - 0.6247Tc = 0

Sum(Fy) = -0.2981Ta - 0.4082Tb + 0.4685Tc = 0

Sum(Fz) = 0.7454Ta + 0.8165Tb + 0.6247Tc = 0

I'm stuck here. Also...I'm wondering....in my sum(Fz), I think this is where I'd subtract 750....as it is pointing down in the z direction. Is this correct?

Thanks in advance

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# Homework Help: Tension in the cables

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