What are lines, line segment and rays

A line end extends forever in both directions, like this:

A line segment is just part of a line. It has two endpoints, like this:

A ray starts at one point and continues on forever in one direction, like this:

In geometry, if any scalar quantization is characterized by the sum of a linear sequence, it describes vector quantities with curves, ie, the vector dimension is represented by a given length and direction with a segment. The length of the segment must be equal to the numerical value of the vector value on a certain scale, and the direction must be exactly the same as its orientation.

Definition. The vector is the orientation, the beginning and the end of the segment.

Thus, the geometric structure of the vector is determined by the length and direction. If A is the starting point of the vector, B is the end point (or end) of the vector. The direction of the vector is taken from the beginning to the end , with the arrow on the vector arrow. (Figure 1). In most cases, the vector is labeled with one letter, for example, and so on.

Definition. The module or the length of the vector indicates the distance between its head and its ends. the vector module is set or set . The vector is divided into three types: a fixed vector, a sliding vector, a free vector.

A fixed vector indicates to the vector that the starting point is fixed at a certain point and can not be moved to a point. For example, if the force is tied to a specific point, it can not be moved to another location.

A sliding vector is a vector that moves along a straight line. For example, the force or speed affecting a solid body can be a vector of the slider. This vector moves to any point along the line itself and can not move to a point in a straight line.

A free vector means that the same vector is a vector that can move along a line and pass itself to a parallel, ie, if the starting point of the vector moves to any point in space, such a vector is called a free vector. In mechanics and physics, these three types of vectors are also encountered, and free vectors are always used in analytic geometry

If the starting point and the end point of the vectors coincide, then they form a zero vector, the zero vector is denoted by . The zero vector does not have a definite direction, and the length is zero .