Scalar Quantities Most of the physical quantities encountered in physics are either scalar or vector quantities. A scalar quantity is defined as a quantity that has magnitude only. Typical examples of scalar quantities are time, speed, temperature, and volume. A scalar quantity or parameter has no directional component, only magnitude. For example, the units for time (minutes, days, hours, etc.) represent an amount of time only and tell nothing of direction. Additional examples of scalar quantities are density, mass, and energy. Vector Quantities A vector quantity is defined as a quantity that has both magnitude and direction. To work with vector quantities, one must know the method for representing these quantities. Magnitude, or "size" of a vector, is also referred to as the vector`s "displacement." It can be thought of as the scalar portion of the vector and is represented by the length of the vector. By definition, a vector has both magnitude and direction. Direction indicates how the vector is oriented relative to some reference axis, as shown in Figure 1. Using north/south and east/west reference axes, vector "A" is oriented in the NE quadrant with a direction of 45 north of the o EW axis. Giving direction to scalar "A" makes it a vector. The length of "A" is representative of its magnitude or displacement.

The magnitude of vector is called scalar vector and The dot product of two vector is a scalar.Scalar vector obeys the commutative and distribution law`s respectvally a.b=b.a and a(b+c)=(a.b)+(a.c).The scalar product of two parallel vectors is maximum is a.b=|a|.|b|.cos (0)=a.b . The scalar product of two opposite vectors is 0. The scalar product of two perpendicular vector`s is o because angle is 90.It is specified completely by a single number.EX:-Distance between two points,Mass of object,Temperature of the body ect...