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Homework Help: Electric Potential Car Battery Problem

  1. Apr 15, 2008 #1
    1. The problem statement, all variables and given/known data
    A particular 12V car battery can send a total charge of 84 A-h (ampere-hours) through a circuit, from one terminal to the other. (a) How many coulombs of charge does this represent? (b) If this entire charge undergoes a change in electric potential of 12V, how much energy is involved?


    2. Relevant equations



    3. The attempt at a solution
    I'd just like some advice in starting the question, simply because I'm not accustomed to working in Ampere-hours. Just a hint would do nicely.
     
  2. jcsd
  3. Apr 15, 2008 #2
    Ampere-hours = 1A*1h
    so, they multiplied their current by the time
    and now just use simple formulas ..
    i = change in q/change in time ..
     
  4. Apr 15, 2008 #3
    I'm still not sure how thew book gets an answer of 3.0 x 10^5 C
     
  5. Apr 15, 2008 #4
    Anyone got any other hints?
     
  6. Apr 15, 2008 #5

    Dick

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    I think an amp is 1 coulomb per second. What do you think it is? That's a hint, son.
     
  7. Apr 15, 2008 #6
    So for an hour the charge would be 84 * 60?
     
  8. Apr 15, 2008 #7

    Dick

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    It would be if an hour were equal to 60 seconds. But it isn't.
     
    Last edited: Apr 15, 2008
  9. Apr 15, 2008 #8
    Ohhhhhhhhhhhh, alright, I get it. It's a simple dimensional analysis problem. Yeesh, why didn't I realize that...
     
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