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!

The dot product.

  1. Nov 24, 2004 #1
    I'm sorry if this is placed under the wrong section of the forum.

    But i really need help with a problem.

    Well, here it is;

    Find a unit vector that is parallel to the xy-plane and perpendicular to the vector 4i - 3j + k *note* there is a ^ above the ijk.
  2. jcsd
  3. Nov 24, 2004 #2


    User Avatar
    Staff Emeritus
    Science Advisor
    Gold Member

    Can you write down an algebraic condition for a vector to be parallel to the xy plane?
    What about for a vector to be perpendicular to 4i-3j+k?
    And for a vector to be a unit vector?
  4. Nov 25, 2004 #3


    User Avatar
    Science Advisor
    Homework Helper

    If the vector is parallel to the xy plane, it must be perpendicular to the z-axis. Unit vector k lies on the z-axis. So, if you find a vector that's perpendicular to both unit vector k and your vector, it will solve your problem.

    Whenever you take the cross product of two vectors, the result is perpendicular to both of the original vectors.
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook

Similar Discussions: The dot product.
  1. Dot product (Replies: 10)

  2. Dot product (Replies: 10)

  3. Dot product (Replies: 2)

  4. Dot product (Replies: 4)