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Easy problem still wrong answer

  1. Jul 10, 2005 #1
    How much work is needed to move a proton from a point with a potential of +630V to a point where it is -60.0V?

    Ok so wouldn't I just use the equation:

    (Va-Vb)=Wba/q
    (-60-630)=Wba/(1.6 x 10^-19)
    Wba=-1.104 x 10^-16 J
     
  2. jcsd
  3. Jul 10, 2005 #2

    James R

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    Your equation looks fine to me. What's the answer you expected?
     
  4. Jul 10, 2005 #3
    Wba=-1.104 x 10^-16 J

    But i keep entering it into the CAPA and it says wrong answer...
     
  5. Jul 10, 2005 #4

    James R

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    Try it without the negative sign.

    The question is ambiguous, since it doesn't specify who or what is doing the work. If it's the electric field, then the answer is negative. If it's an external force, the answer is positive.
     
  6. Jul 10, 2005 #5

    Pengwuino

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    haha i love problems that are so simple yet you dont get an answer. Makes me start pounding on walls. Something simple has obviously gone unnoticed or like someone said, a negative sign is probably missing. Those negative signs piss me off to no end. Everytime i learn something where im told the answer is always positive, i go to church for 40 hours straight to thank god for all the good he has done in the world such as the current subject i was just taught.

    I truely hate negatives....
     
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