Scalars and Vectors
For instance, distance, length, speed, temperature, voltage, mass, pressure, and work are scalars.
A vector is a quantity that is determined by both its magnitude and its direction and hence it is a directed line segment.
For instance, force, displacement, and velocity (which gives the speed and direction of the motion) are vectors.
We denote vectors by lower case letters with arrow. A two dimensional vector is a directed line segment in R2 and a three dimensional vector is a directed line segment in R3.