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Homework Help: Find Angle of the Vector

  1. Jan 16, 2009 #1
    The angle (in degrees) between A = -24.5i + 45.4j, and the positive x-axis is?
     
  2. jcsd
  3. Jan 16, 2009 #2

    rl.bhat

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    If A = xi + yj, then tan(theta) = y/x
     
  4. Jan 16, 2009 #3
    i still dont know how to figure out the angle im confused
    i know the magnitude of the vector is 38.3 but what is the x or y component
     
  5. Jan 16, 2009 #4
    actually i figured it out all i had to do was set tan-1(45.4/-24.5) and got 61.65 and then added the 28.35 which was the extra onto the already existing 90 degrees and got 118.35 deg
    thank you
     
  6. Jan 16, 2009 #5

    rl.bhat

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    In this vector, x component is -24.5 and y component is 45.4. To find the angle the magnitude of the vector in not needed.
    And the magnitude of the vector is given by (x^2 + y^2)^1/2
     
  7. Jan 16, 2009 #6

    rl.bhat

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    You have to wright it as -118.35 deg, because according to convention, if you measure the angle from the x axis in the antyclockwise direction, the angle is positive. Otherwise it is negative.
     
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