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Homework Help: A mechanics question about work and vectors

  1. Nov 13, 2012 #1
    this year i started studying physics, so this question might be easy but i couldn't do it... i'll be happy if you help me.

    ''A constant force (5N)i-7(N)j is applied on an object and it moves. The total displacement of the object is l=(3)i+(6)j+(3)k. Find the angle between the force and the displacement.''
  2. jcsd
  3. Nov 13, 2012 #2


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    Homework Helper
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    What specifically do you need help (or are having trouble) with? Please elaborate.
  4. Nov 13, 2012 #3
    I don't know how to find the angle. How can I use the displacement information to find the angle?
  5. Nov 13, 2012 #4
    How is the dot product of two vectors related to the angle between them?
  6. Nov 14, 2012 #5
    Ah yes! Thank you very much. ^^
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