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Homework Help: Adding Vectors by Components

  1. Jan 30, 2009 #1
    1. The problem statement, all variables and given/known data

    "a" vector - "b" vector = 7m(i) + -3.5m(j) + -4.5m(k)

    A third vector "c" vector pops out of nowhere.

    Find the new unit-vector notation such that "a" vector - "b" vector + "c" vector = 0

    ???m(i) + ???m(j) + ???m(k)

    2. Relevant equations

    a - b + c = 0

    3. The attempt at a solution

    c = b - a? <<< How do you do it backwards?
  2. jcsd
  3. Jan 30, 2009 #2
    You are given A-B, so they said they added another vector C...

    So you have (A-B)+C=0, Since you already know A-B, you just have to find a vector that you can add to that which will sum up to zero.

    remember i=x, j=y, k=z and you can only add x to x and y to x and z to z.

    So its just basic math really. here is an example which should point you in the right direction.

    <1,5> +<-1,-5>=<0,0>
  4. Jan 30, 2009 #3
    Change the signs. Thanks NationalBasketballAssociationJamOneHundred!
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