stated if the dimensions are those
of a pure number. The orientation of a vector is specified by the relationship
between the vector and given reference lines and/or planes. The sense of a
vector is specified by the order of two points on a line parallel to the vector.
Orientation and sense together determine the direction of a vector. The line
of action of a vector is a hypothetical infinite straight line collinear with the
vector. Vectors are denoted by bold face letters, e.g., a, b, A, B, CD. The
symbol |v| represents the magnitude (or module, or absolute value) of the
vector v. The vectors are depicted either by straight or curved arrows. A
vector represented by a straight arrow has the direction indicated by the
arrow. The direction of a vector represented by a curved arrow is the same
as the direction in which the right-handed screw moves when the screw’s axis
is normal to the plane in which the arrow is drawn and the screw is rotated
as indicated by the arrow.