(i) Equal vector: Two vectors are said to be equal vectors, if they have equal magnitude and same direction.
Figure (i) shows the two vectors having same magnitude and same direction, therefore, they are equal vectors.
(ii) Negative vector: A vector is said to be negative of another vector if they have same magnitude but are in opposite direction.
(iii) Parallel vector: If the lines of action of the two vectors are same or parallel to each other, then the vectors are parallel. The magnitude of two vectors need not to be equal for parallel vectors.
The parallel vectors are of two types:
(a) Like parallel vector: Two vectors are said to be like parallel vectors if they have same direction.
(b) Unlike parallel vectors: Two vectors in the opposite direction are called unlike parallel vectors.
(iv) Co-planer vectors: The vectors lying in one plane are called co-planer vectors.
(v) Co-initial vectors: The vectors having common initial point are called co-initial vectors.
(vi) Co-linear vectors: The vectors having same line of action are called co-linear vectors.
What are the basic characteristics that a quantity must possess so that it may be a vector quantity?
A quantity must possess the direction and must follow the vector axioms. Any quantity that follows the vector axioms are classified as vectors.