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Homework Help: Average Resultant Force

  1. Nov 5, 2007 #1
    [SOLVED] Average Resultant Force

    Hi for this question
    http://tinyurl.com/3cbxlq

    What I try is
    Average Force
    =(mv-mu)/t
    =2000(6-4)/4
    =1000
    but this is not one of the answers. Meaning it is wrong.

    May I know how to do this question?
     
  2. jcsd
  3. Nov 5, 2007 #2

    Astronuc

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    Well one has to take the difference between two vectors which are orthogonal (90°). So find the resultant vector and divide by the time to obtain the average acceleration.

    [tex]\frac{\Delta\vec{F}}{\Delta{t}}\,=\,m\frac{\vec{v_f}-\vec{v_i}}{\Delta{t}}[/tex]

    Assume the truck's initial speed is 6 i m/s and it takes a right turn and has speed 4 j m/s, where i and j are unit vectors in the x and y directions
     
    Last edited: Nov 5, 2007
  4. Nov 5, 2007 #3
    Got it, thanks :) Using magnitude of vector to get the answer, it is c.
     
  5. Nov 5, 2007 #4

    Astronuc

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    Correct! :cool:
     
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