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What are the two possibilities for its x component?

  1. Sep 17, 2007 #1
    You are given a vector in the xy plane that has a magnitude of 85.0 units and a y component of -40.0 units.
    (a) What are the two possibilities for its x component?
    ____
    ____
    (b) Assuming the x component is known to be positive, specify the vector which, if you add it to the original one would give a resultant vector that is 85.0 units long and points entirely in the -x direction.
    Magnitude
    ____
    Direction
    ____°
     
  2. jcsd
  3. Sep 17, 2007 #2
    A. Start by using your Magnitude Formula (pythagorean theorem) and look x value (you will get 2 as its a square root).
     
  4. Sep 17, 2007 #3
    93.9 and -93.9?
     
  5. Sep 17, 2007 #4

    learningphysics

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    Homework Helper

    careful. (x-component)^2 + (y-component)^2 = magnitude^2.
     
  6. Sep 17, 2007 #5
    thanks. i got it 75 and -75. now what is the second part of the question asking? would it be -85?
     
  7. Sep 17, 2007 #6

    learningphysics

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    No. Just use vector algebra. What is the original vector? what is the resultant vector? write them in the form [tex]x\vec{i} + y\vec{j}[/tex].
     
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