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Vectors and "displacement"

  1. Nov 17, 2014 #1
    I'm just starting to learn about vectors, and I was trying to figure out what the vector components mean physically. I've seen two definitions of vectors, and the first is a that a vector is something with a size and a direction. The second definition I saw defined vectors as "displacements in space" and that given an example vector, say (3,4,1) that would represent a displacement of 3 in the x direction, 4 in the y direction and 1 in the z direction.

    This made a lot of sense to me intuitively - that looking at it as displacement would explain why parallel vectors are equal and why vectors are coordinate-independent. However, although I don't know much about it, I know displacement is defined to be a vector in itself, so I can't see how it could be part of the definition of a vector.

    So my question is, do vector components represent displacement? And if the don't, what physical quantity/term do they represent?

    Thanks :)
  2. jcsd
  3. Nov 17, 2014 #2


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    Vector components are just other vectors, albeit ones which are usually parallel with a coordinate system or other convenient reference. Vectors can be used to represent positions in space, forces, moments, or other quantities which are composed of a magnitude and a direction.
  4. Nov 17, 2014 #3


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    The way I read this, it seems the wrong way round. Displacement is an example of a Vector. A Vector is not (necessarily) a Displacement.
    The components represent the same quantity as the original vector. The 'deeper' significance of what they mean is that they can be just an abstraction. There doesn't have to be a Force, Displacement or E Field in that particular direction. It's just convenient for the purpose of doing the calculation.
  5. Nov 18, 2014 #4
    Thank you both :) I think I understand now.
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