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# Thread: Any electrical engineers? Help!

1. ## Any electrical engineers? Help!

Hey guys,

I've got this physics problem here, and I know the answer, but I don't know why it is the answer. The answer is A, 1 amp. If you can take me through step-by-step as to how you arrive at A, I would greatly appreciate it! In fact, I'll give you 4 pics of a very famous fitness model, nude, who has competed in the fitness olympia(I'm not going to say her name just to be safe, because on her website she's got this whole big disclaimer deal about distrubiting pics).

Alright here it is:

2. New Member
Join Date
Dec 2002
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Tampa Bay, Florida
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you need to do nodal analysis at the node to the right of the 12ohm resistor, where x is the voltage at that node.

the equation is.....

(x-16)/4 + (x-18)/12 + (x-0)/8 = 0

solve for x and you get x=12

so to get the current at the 4ohm resistor just use ohms law, i=v/r

i=(16V-12V)/4=1A

Hope that helps.

Ice

3. Ok I almost understand that whole thing. So, you're saying that on the one side of the resistor you have 16 volts, and on the other you have 12 volts...so you subtract the two? The you have 4 volts, so 4/4=1. Is that right?

And when you said "at the node to the right of the 12ohm resistor", did you mean the node at the right of the 4ohm resistor?

I was thinking that you had to test it by taking out 1 battery first, then seeing what voltage passed through on one side, and then replace the battery you took out and take out the other one, and then find the voltage passed through on the other side, and then subtract. But your method is sooo much easier! Thanks!!!!!