Trying to apply superposition method to circuit, not working

AI Thread Summary
The discussion revolves around the application of the superposition method to calculate power in a double loop circuit with two EMFs. The user attempted to find the power dissipated in a 6 Ω resistor by replacing each battery with a short circuit and summing the resulting currents and voltages. However, it was clarified that power cannot be directly added using superposition; instead, the total current should be calculated first, followed by using the formula P = I²R. An alternative method suggested involves calculating individual voltages and then applying the power formula. The key takeaway is that the superposition principle applies to current and voltage, but not directly to power calculations.
TheKShaugh
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Homework Statement



A double loop circuit is shown in the figure below.[/B]
FVTMCtE.png

The Emf
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x = 6.00 V and the Emf
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w = 19.00 V. Both are shown on the diagram. Calculate the power dissipated in the 6 Ω resistor located on the extreme right in the circuit.

Homework Equations



V=IR, P=VI

The Attempt at a Solution



I tried using superposition, where I replaced one battery with a short and solved for the voltage and current through the 6 ohm resistor, and the did the same by replacing the other battery with a short. The total current and voltage is the sum of the individual values. I plugged those final values into P=VI and got the wrong answer. Should this method work and I just did the work wrong or is there something I'm not aware of?
 
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Sounds like you did it right but without your posting your work it's impossible for us to see where you might have gone wrong.
 
TheKShaugh said:
I tried using superposition, where I replaced one battery with a short and solved for the voltage and current through the 6 ohm resistor, and then did the same by replacing the other battery with a short. The total current and voltage is the sum of the individual values. I plugged those final values into P=VI and got the wrong answer. Should this method work and I just did the work wrong or is there something I'm not aware of?
You cannot add power by superposition. You can compute current I by superposition:
I = I1 + I2.
Then P = I^2 R.
Or you could have computed V1 and V2 by superposition, then P = VI = (V1 + V2)(V1 + V2)/R.
 
rude man said:
You cannot add power by superposition. You can compute current I by superposition:
I = I1 + I2.
Then P = I^2 R.
Or you could have computed V1 and V2 by superposition, then P = VI = (V1 + V2)(V1 + V2)/R.
DOH ! I assumed that's what he was doing but on rereading I see I just glossed over what he really said. Good catch.
 
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