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Fundamentals of Mechanics/Units and Vectors/Coordinate Systems
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Vector Algebra Vectors in Terms of Their Components
To specify the location of a point in space, a coordinate system must be used. A coordinate system consists of a reference point called the origin O and a set of labeled axes. The positive direction of an axis is in the direction of increasing numbers, whereas the negative direction is opposite. Figures 1.16 and 1.17 show the rectangular (or Cartesian) coordinate system and the polar coordinates of a point, respectively. The rectangular coordinates x and y are related to the polar coordinates r and θ by the following relations: