(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

**Physics Forums | Science Articles, Homework Help, Discussion**

Join Physics Forums Today!

The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

# Tension in the cables

**Physics Forums | Science Articles, Homework Help, Discussion**