Question

A vector u for which $\left|u\right|$= 1 is called a ______ vector.

Short answer

A vector u for which |u|= 1 is called an unit vector.

Step-by-step solution

Step 1. Unit vector

A vector is a quantity that has both magnitude, as well as direction. A vector that has a magnitude of 1 is a unit vector. It is also known as direction vector.

Unit vectors are usually determined to form the base of a vector space. Every vector in the space can be expressed as a linear combination of unit vectors. The dot products of two unit vectors is a scalar quantity whereas the cross product of two arbitrary unit vectors results in third vector orthogonal to both of them.

Step 2. Graph 

As shown in the graph there is a vector AB whose magnitude is u which is equal to 1 .Hence this vector is known as a unit vector.