### Scalar and Vectors - Explanation

The motion of objects can be described by words. Even a person without a background in physics has a collection of words that can be used to describe moving objects. Words and phrases such as going fast, stopped, slowing down,speeding up, and turning provide a sufficient vocabulary for describing the motion of objects.

In physics, we use these words and many more. We will be expanding upon this vocabulary list with words such as distance, displacement,speed, velocity, and acceleration. As we will soon see, these words are associated with mathematical quantities that have strict definitions. The mathematical quantities that are used to describe the motion of objects can be divided into two categories.
The quantity is either a vector or a scalar. These two categories can be distinguished from one another by their distinct definitions:

• Scalars are quantities that are fully described by a magnitude (or numerical value) alone.
• Vectors are quantities that are fully described by both a magnitude and a direction.
Examples:

Scalar Quantity : Mass,Time,Temperature and Electric Potential.

Mass is a Scalar Quantity Because it is Fully Described by Size.

Ex:
5 m - Scalar Quantity
20 degrees Celsius - Scalar Quantity

Vector Quantity : Weight,Force,Velocity,Electric Field intensity and Electric Flux.

A Vector can be represented geometrically by an arrow

Weight is a vector quantity because it has direction ( the weight of an object pushes down due to gravity)

Ex:
30 m/sec, East - Vector Quantity.

Thanks to:
Source: http://www.nasa.gov/
Source: http://www.physicsclassroom.com