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Unit vector

  1. Dec 7, 2009 #1
    Why are rectangular unit vectors constant in time whereas those of a polar coordinate or spherical coordinate system aren't?
  2. jcsd
  3. Dec 7, 2009 #2
    How is anything changing in time? You need to be waaaay more specific.
  4. Dec 8, 2009 #3
    Could you help me figure out how I can be more specific?
  5. Dec 8, 2009 #4


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    THe unit vector in the x-direction is orthogonal to the surface x=some constant (i.e, planes).

    Thus, all these unit vectors in the x-direction are PARALLELL to each other, and thus, essentially, the same vector.

    The radial vector, however, is orthogonal to the surface r=some constant (i.e, spheres)

    Along each such surface, non-paralllell radial vectors abound, and thus, the unit radial vactor is NOT the same at different points on the surface.
  6. Dec 8, 2009 #5
    I believe that makes sense, thank you!
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