Question

What are scalar and vector quantities?

Answer 1

Scalars and Vectors
A scalar quantity has only magnitude. A vector quantity has both magnitude and direction.

Scalar Quantities
Length, area, Volume speed mass, density pressure temperature energy, entropy work, power

Vector Quantities.
Displacement velocity acceleration momentum force lift, drag, thrust weight

For example, the volume of an object, the three-dimensional space that an object occupies, does not depend on direction. If we have a 5 cubic foot block of iron and we move it up and down and then left and right, we still have a 5 cubic foot block of iron. On the other hand, the location, of an object does depend on direction. If we move the 5 cubic foot block 5 miles to the north, the resulting location is very different than if we moved it 5 miles to the east. Mathematicians and scientists call a quantity which depends on the direction a vector quantity. A quantity which does not depend on direction is called a scalar quantity.

Vector quantities have two characteristics, a magnitude, and a direction. Scalar quantities have only a magnitude. When comparing two vector quantities of the same type, you have to compare both the magnitude and the direction. For scalars, you only have to compare the magnitude. When doing any mathematical operation on a vector quantity (like adding, subtracting, multiplying) you have to consider both the magnitude and the direction.