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Homework Help: Vector forces.

  1. Aug 13, 2010 #1
    1. The problem statement, all variables and given/known data
    I got two forces acting on an object. I have the magnitude of the forces, 6 N and 2 N. Then i'm asked to find out what force is impossible to produce with these two forces.


    2. Relevant equations



    3. The attempt at a solution

    I have no idea where to begin with. Maybe i didn't think hard enough...
     
  2. jcsd
  3. Aug 13, 2010 #2
    Are you sure it's not just asking for an example of a force that can't be produced? This is a very weird question because the number of possible answers is infinite.
    Post the exact wording of the question.
     
  4. Aug 13, 2010 #3
    Theres a choice between 2N and 6N. Sorry. It's a multiple choice question. The other 2 answers are 8N and 4N which is quite obviously can be produced.
     
  5. Aug 13, 2010 #4
    Try drawing some triangles.You will see that only one of those vectors can be produced by adding the given vectors.
     
  6. Aug 13, 2010 #5
    It will be an isosceles triangle right ?
     
  7. Aug 13, 2010 #6
    Okay i found out the answers by using cosine rule. Are there some insights on this matter ? lol..
     
  8. Aug 13, 2010 #7
    Yes since you want to get either 6N or 2N using a 6N and a 2N.


    edit:
    The exercise is meant to teach you to watch out for answers that do no make sense.
     
    Last edited: Aug 13, 2010
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