** 1. Null Vector or Zero Vector**

Note : A null vector has no definite direction.

Unit Vector : A vector whose length is unity is called a unity vector . The unit vector in the

**2. direction of vector .**

Note 1. Any vector is equal to its modulus multiplied by a unit vector in that direction.

**3. Proper Vector**

Any non zero vector is called a proper vector .

**4. Like and unlike vectors**

Vectors having the same direction are called like vectors and vectors having the opposite directions are called unlike vectors .

**5. Collinear vectors**

Vectors which have the same or parallel support , are called collinear vectors .

**6. Coplanar vectors**

Vectors which lie in the same plane or parallel to same plane are called coplanar vectors.

**7. Co initial vectors**

Vectors having the same starting point are called co-initial vectors.

**8. Reciprocal Vectors**

Two vectors are said to be reciprocal vectors when they have the same direction and product of their lengths is one.

**9. Equal vectors**

Two vectors are said to be equal if they have

- the same magnitude
- the same sense
- the same or parallel support

** 10. Localised vector**

A vector whose initial point is fixed is called a localised vector.

Example force is a localised vector.

** 11. Free vector**

A vector whose initial point is not fixed is called a free vector .