Physics Midterm Explanation Kirkoff Rule

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SUMMARY

The discussion centers on applying Kirchhoff's Voltage Law to a circuit problem involving a 5.00 ohm resistor. The user initially calculated the current using the equation -3A(15 Ohms) + 50 V + I(5) = 0, resulting in an incorrect current of -1 A. The correct current should be 2.5 A, indicating a misunderstanding of current flow assumptions in the circuit. The user must recognize that currents can change and should not be assumed constant without verification.

PREREQUISITES
  • Understanding of Kirchhoff's Voltage Law
  • Basic circuit analysis techniques
  • Familiarity with Ohm's Law
  • Ability to interpret circuit diagrams
NEXT STEPS
  • Review Kirchhoff's Laws in detail
  • Practice circuit analysis problems involving multiple loops
  • Learn about current division in parallel circuits
  • Explore the concept of node voltage analysis
USEFUL FOR

Students studying electrical engineering, physics students preparing for exams, and anyone looking to improve their circuit analysis skills.

Nimmy
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Its the part c question...which states

C) Suppose we made V = 0. Find the new current running through the 5.00 ohm resistor.So I just took the biggest loop and did it this way

Sum of V = 0

So starting at the upper left hand corner of the circuit

-3A(15 Ohms) + 50 V + I (5) = 0

-45 + 50 +5I = 0

5 +5I = 0
I = -1 A

Which is not correct. The answer I think is supposed to be 2.5 Amps but can you tell me what mistake I'm making here.
 

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I assume the currents labeled in the diagram are from an earlier part of the problem. You can't just assume that the currents remain the same.
 

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