1. Not finding help here? Sign up for a free 30min 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!

Vector rotation

  1. Nov 30, 2008 #1
    1. The problem statement, all variables and given/known data

    Rotate a vector v=x_1e_1+x_2e_2 90 degrees by using the rotation matrix.

    3. The attempt at a solution

    As you can see in the attached image, I get a 90 degree clockwise rotation. I'm supposed to get a 90 degree counterclockwise rotation. Where do I go wrong?
     

    Attached Files:

  2. jcsd
  3. Nov 30, 2008 #2

    tiny-tim

    User Avatar
    Science Advisor
    Homework Helper

    Hi _Andreas! :smile:
    erm … not enough sleep? :redface:

    Hint: try multiplying by -1 :smile:
     
  4. Nov 30, 2008 #3

    gabbagabbahey

    User Avatar
    Homework Helper
    Gold Member

    What you've drawn for your rotated vector is [itex]x_1 \hat{e_1} - x_2 \hat{e_2}[/itex]; which is not the same as what you calculated using the transformation matrix: [tex]\vec{y}=\begin{pmatrix} -x_2 \\ x_1 \end{pmatrix}=-x_2 \hat{e_1} + x_1 \hat{e_2}[/tex]
     
  5. Nov 30, 2008 #4
    Thanks! I did suspect that this was the case, but I wasn't sure.
     
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook

Have something to add?



Similar Discussions: Vector rotation
  1. Earth rotating (Replies: 5)

  2. Quaternion rotations (Replies: 3)

  3. Rotation on a plane (Replies: 3)

Loading...