Page 4 - mechanics

Chapter – 1 Introduction

In one dimensional problem, a coordinate is a signed
number that indicates the point distance and position relative to
the zero point. The number indicates its distance from to the
zero point and the sign indicates whether the point lies in
positive or negative half of the line. Note that the line can be
inclined at any angle according to the problem.

In a plane, i.e. two dimensional problems, the Cartesian
coordinate system consists of two number scales, called the x
axis and the y axis, that are perpendicular and intersects at the
reference (zero) point called the origin usually denoted by O.
This divides the plane into four quadrants as shown in Figure
(1.2).

y

Quadrant II Quadrant I

O x
Quadrant III Quadrant IV

Fig. 1.2 Two dimensional coordinate system.
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