1.1. Introduction
Learning Objectives
By the end of this chapter, you will be able to:
- List physical quantities and their corresponding SI units;
- Convert units from one system of measurement to another;
- Solve problems involving length, area, and volume.
Introduction
In industrial settings and in real life, we are exposed to a lot of information regarding the size of various physical quantities. This size can present itself in the form of a length, area, speed, etc.
To be able to interpret and make sense out of these quantities we need to use a standardized system of units. These units help us describe and compare physical quantities in a meaningful way.
The magnitude (size) of a physical quantity does not tell the whole story if it is not accompanied by a unit. For example, if we say that a crate is subjected to a horizontal pulling force of 120, we do not know the amount of force, since the information could mean: 120 N, 120 lbs., 120 MN, 120 kN, etc. Unless followed by a unit, the magnitude is not helpful in any calculations, conclusions, or interpretations.
