# How to properly find equilibrium vectors when 3 or 4 vectors are present? [closed]

I'm having trouble regarding how to find the equilibrium of vectors. We were given tables with given information and had to fill them in; I'm fairly sure my initial attempts were incorrect.

first example

Vector A: mass - .2kg, magnitude - ?, direction - 20deg, xcomp -?, ycomp - ?
Vector B: mass - .15kg, magnitude -?, direction 80deg, xcomp - ?, ycomp - ?
Vector C: mass - ?, magnitude -?, direction -?, xcomp ?, ycomp - ?


A and B are no problem, I'm just not sure if I add or subtract my components to get the components for C.

The same goes for this one:

Vector A: mass - ?, magnitude - ?, direction - 0deg, xcomp - ?, ycomp - ?
Vector B: mass - ?, magnitude - ?, direction - 90deg, xcomp - ?, ycomp - ?
Vector C: mass - .3, magnitude - ?, direction - 240deg, xcomp - ?, ycomp - ?


and the oddest one:

Vector A: mass - .1, magnitude - ?, dir - 30deg, xcomp - ?, ycomp - ?
Vector B: mass - .2, magnitude - ?, direction - 90deg, xcomp - ?, ycomp - ?
Vector C: mass - .3, magnitude - ?, direction - 225deg, xcomp - ?, ycomp - ?
Vector D: mass - ?, magnitude - ?, direction - ?, xcomp - ?, ycomp - ?


NOTE: I was using f = ma, tan(angle) = a/b, and xcomp = fcos(angle) and ycomp = fsin(angle) I just didn't know what to do about the final vectors for sure.

NOTE 2: I don't need help finding the first few vectors' information, just the last ones (e.g. Vector D). More specifically, when do I add or subtract the components of the first vectors in order to get the components for the final vector and then get the rest of the information for it?

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## closed as too localized by Qmechanic♦, Emilio Pisanty, Sklivvz♦, Manishearth♦Dec 27 '12 at 16:35

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