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Homework Help: Multiplying Vectors Problem

  1. Sep 13, 2009 #1
    1. The problem statement, all variables and given/known data
    In a meeting of mimes, mime 1 goes through a displacement d1 = (2.79 m)i + (3.53 m)j and and mime 2 goes through a displacement d2 = (-6.75 m)i + (5.3 m)j. What are (a)|d1 × d2|, (b)d1 · d2, (c)(d1 + d2) · d2, and (d) the component of d1 along the direction of d2?
    Give your answers in standard SI units.

    2. Relevant equations
    vectors a dot b = axbx + ayby + azbz


    3. The attempt at a solution
    I got part a and c, but not b and d.

    For part b isn't it (-18.8)(1) + 0 + 0 + (18.7)(1) = -.1? I don't know what part d is asking for.
     
  2. jcsd
  3. Sep 13, 2009 #2
    For Part B i got -18.83i +18.71j
     
  4. Sep 13, 2009 #3
    sorry did not realize my answer was the same as yours!
     
  5. Sep 13, 2009 #4
    Haha, no problem. The thing is I have to enter the answers on the computer, but apparently my answer is wrong.
     
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