Trying to apply superposition method to circuit, not working

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Homework Help Overview

The discussion revolves around a double loop circuit problem involving two EMFs and a 6 Ω resistor. The original poster attempts to apply the superposition method to calculate the power dissipated in the resistor but encounters an incorrect result.

Discussion Character

  • Exploratory, Assumption checking, Problem interpretation

Approaches and Questions Raised

  • Participants discuss the application of the superposition method, questioning whether it is appropriate for calculating power directly. There is an exploration of how to correctly apply the method to find current or voltage before calculating power.

Discussion Status

Some participants provide guidance on the correct application of superposition, emphasizing that power cannot be added directly. There is an acknowledgment of the need for clarity in the original poster's work to identify potential errors.

Contextual Notes

Participants note that the original poster did not provide detailed calculations, which limits the ability to diagnose the issue. There is an implicit understanding of homework constraints regarding the use of specific methods.

TheKShaugh
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Homework Statement



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

The Emf
mimetex.gif
x = 6.00 V and the Emf
mimetex.gif
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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