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Homework Help: Force Vector Magnitude Distance

  1. Oct 21, 2013 #1
    1. The problem statement, all variables and given/known data
    A force of f= i + 2j- 3k is applied to a particle that moves 10 feet in the direction of i + j. How much work is done?

    2. Relevant equations
    W= ||F|| dot product d

    3. The attempt at a solution
    D= 10 cos 45 i + 10 sin 45 j
    D= 5sqrt(2) i + 5 sqrt(2) j
    F= i + 2j - 3k

    W= ||F|| dot product d
    W= sqrt(14) dot product (5sqrt(2)i + 5sqrt(2)j)
    W= 5sqrt(28) + 5 sqrt(28)
    W= 10sqrt(28)
    W= 20sqrt(7)
    Is this even right? Thanks!
  2. jcsd
  3. Oct 21, 2013 #2


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    Science Advisor
    Homework Helper
    Gold Member

    ##\| F\|## is a scalar and you can't dot a scalar and a vector.

    No, it is not correct. You have F and D correct. Look up the correct formula for work.
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