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

2. Relevant equations

M = r x F, where r is "a vector directed from the line of action of one of the forces to the line of action of any other force"

3. The attempt at a solution

Well, for the 250 lb couple the r = {3i - 4j - 2k{, F = 250 {3/5i - 4/5j}

M = {-400i - 300j} (I verified this by taking the moments individually)

For F1, r = 3i and F = f_{y}j

so M = 3F_{y}*k

For F2, r = {-2k} F = {f_{x}i} so M = {-2F_{x}j}

When we sum the moments, we get {-400i -300 - 2F_{x}j + 3F_{y}k }

The x component can never equal zero!

There are two possibilities: I'm misreading the diagram, I'm missing something entirely, or I don't understand the couples idea of getting the vector r between two forces. Please help, i've been doing this for over 5 hours now.

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# Homework Help: STATICS couples problem (I solved it but it doesnt make sense!)

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