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Homework Help: Current in a Battery

  1. Sep 26, 2010 #1


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    1. The problem statement, all variables and given/known data
    A dead battery is charged by connecting it to the live battery of another car with jumper cables. Assume that V = 5.5 V and R = 0.50 .

    What is the current of the starter and the current of the dead battery?

    2. Relevant equations
    I=V/R, I1=I2+I3, basically Kirchoff's law...

    3. The attempt at a solution
    I thought for finding the current of the starter all, you had to do was use I=V/R, so it would 5.5/.50, but it came out wrong :(. I then tried multiplying the two resistances together..still no luck, and did V/R..still no luck, however I found that the answer comes out to be 170-171, and how I have no idea how to get that. I also tried finding the current and then subtracting it from the intial voltage and divide by the intial resistance..when I did that, I got somewhere in the 100's, but no where near the answer. I came up with millions of techniques, but none worked. Can someone help? I'm really stuck on this.


    Attached Files:

  2. jcsd
  3. Sep 26, 2010 #2
    You've got 3 unknowns, which are [tex]I_1, I_2, I_3 [/tex]

    Now search 3 equations that can solve your unknowns.
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