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Electric Force Textbook error?

  1. Jan 27, 2013 #1
    1. The problem statement, all variables and given/known data

    Find the net force given a point charge and the value of the electric field.



    2. Relevant equations

    FE = εq

    ε= (5.6*10^4)
    q=(-1.2 * 10^-5)

    3. The attempt at a solution

    FE = εq
    FE = (5.6*10^4)(-1.2 * 10^-5)
    FE = 0.672 N


    Seriously. I am posting this question.

    Here's the answer the book gave:

    FE = εq
    FE = (5.6*10^4)(-1.2 * 10^-5)
    FE = (6.7*10^4) N


    It does this again on the answer to the next question, increasing the magnitude by 10^5.

    Everything I know tells me I'm right but I need to be sure I'm not doing something very wrong. I don't know why this text is still in circulation if its riddled with this many errors.​
     
  2. jcsd
  3. Jan 27, 2013 #2

    gneill

    User Avatar

    Staff: Mentor

    Did the question supply units to associate with the field and charge values?
     
  4. Jan 27, 2013 #3
    xxxx
     
    Last edited: Jan 27, 2013
  5. Jan 27, 2013 #4
    charge is in coulombs

    field is in newtons per coulomb
     
  6. Jan 27, 2013 #5
    xxxx
     
    Last edited: Jan 27, 2013
  7. Jan 27, 2013 #6

    gneill

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    Staff: Mentor

    So, coulombs for charge, meters for distances. Looks like your answer is correct and the text is in error.
     
  8. Jan 27, 2013 #7
    Thanks.

    Kind of frustrating, seeing as how we're expected to learn the course solely from the text... which is very inaccurate a lot of the time.
     
  9. Jan 27, 2013 #8
    What is the text, Halliday and Resnick?
     
  10. Jan 27, 2013 #9
    Nah. This place makes their own text for Canadian students.
     
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