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Homework Help: Electric Force

  1. Aug 30, 2008 #1
    Two positive charges q0 at the origin and q1 at (0,d1,0) and one negative charge -q2 at (0,d2,0). What is the net force on particle 0 from particle 1 and 2? (See Picture CPartB inserted at bottom)

    F on 0 due to 1 = kq0q1/d1^2 and since it is in the negative y direction since q1 repels q0 wouldn't F on 0 due to 1 = -kq0q1/d1^2 [tex]\hat{y}[/tex]?

    F on 0 due to 2 = kq0q2/d2^2 and since it is in the positive y direction since q2 attracts q0 wouldn't F on 0 due to 2 = kq0q2/d2^2 [tex]\hat{y}[/tex]?

    So wouldn't the net force = -kq0q1/d1^2 [tex]\hat{y}[/tex] + kq0q2/d2^2 [tex]\hat{y}[/tex]? Would this be the way I type it into mastering physics?

    Thank you for your help. I am having a difficult time figuring out how to input my answers in Mastering Physics.


  2. jcsd
  3. Aug 30, 2008 #2


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    Homework Helper

    Yeah it's ok. I used this software 2 semesters as well as part of my online HW excercises but I can't remember how to enter input.
  4. Aug 30, 2008 #3
    I would hate to lose points on a problem that I got correct just because I did not input the answer correctly into mastering physics. So if there is anyone who does know the syntax I would greatly appreciate any help.

    Thanks for the quick reply.
  5. Aug 30, 2008 #4


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    Homework Helper

    If I remember correctly you have 5 tries, and I believe from my past experience the system is smart enough to recognise correct partial answers which differ from the actual answer by mere syntax. In fact I should say throughout my entire semester when I used it, I only scored a single question wrong solely due to syntax. At other times, the software recognised the answer in improper syntax.

    Having said that, I'm sure there is also a trial MasteringPhysics excercise which teaches you how to enter input in the proper syntax. Check that one out. You're not likely to find help here on how to enter syntax for a specific online software since software do change over time.
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