1. Limited time only! Sign up for a free 30min personal tutor trial with Chegg Tutors
    Dismiss Notice
Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

Calculating the Unit Vectors

  1. Feb 13, 2010 #1
    1. The problem statement, all variables and given/known data
    http://img22.imageshack.us/img22/1254/10031833.jpg [Broken]

    2. Relevant equations

    3. The attempt at a solution
    My attempt was based on the idea that both triangles formed by the vector components (x component, y component, and the hypotenuse which is the magnitude of the vector itself) would be similar.

    I took the length of each of the sides, -3.20 for x and 2.10 for y and individually solved for the unit vector by setting up this relationship:
    (length of component)/(length of hypotenuse)=(length unit component)/1

    The system rejected both of my answers. For x i got -0.836 and for y i got 0.549.
    Last edited by a moderator: May 4, 2017
  2. jcsd
  3. Feb 13, 2010 #2
    Your answer looks fine to me. I calculated the same value for the two components. I like that similar triangle method to find unit vectors. In vector classes, you usually just think about it this way(which involves the exact same math): you have a vector A with magnitude A at angle C. You want the same direction(the same angle C) at a magnitude of 1, so you divide by A(the hypotenuse). So yeah, it's the same calculation: each component divided by the hypotenuse.
    Last edited by a moderator: May 4, 2017
  4. Feb 13, 2010 #3
    Maybe it has to do something with unit vector notation. is there a specific notation?Or maybe we both got the answer wrong. Either way im not getting my homework credit right now
  5. Feb 13, 2010 #4
    please help me figure this out, or at least give me your opinions.
  6. Feb 13, 2010 #5
    What are you calculating here? Are not the components given in the problem?
    The x component is -3.20 and the y component is +2.10, according to the problem. Am I missing something here?
  7. Feb 16, 2010 #6
    it turns out that there isn't any calculation necessary, and your answer is correct. i thought the question was asking for a unit vector with the same angle as the given vector.
    A Unit vector is a vector with a magnitude of 1, thats where all of my calculations came from - which apparently were unnecessary.
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook