Units are labels that are used to distinguish one type of measurable quantity from other types. Length, mass, and time are distinctly different physical quantities, and therefore have different unit names, such as meters, kilograms and seconds. We use several systems of units, including the metric (SI) units, the English (or US customary units), and a number of others, which are of mainly historical interest.
This part of the book contains the following:
International System of Units
Metric Units of Measurement
U. S. Units of Measurement
Tables of Equivalents
The International System of Units, abbreviated as SI, is the modernized version of the metric system established by international agreement.
| Quantity | Name | Symbol |
|---|---|---|
| length | meter | m |
| mass | kilogram | kg |
| time | second | s |
| electric current | ampere | A |
| thermodynamic temperature | kelvin | K |
| amount of a substance | mole | mol |
| Quantity | Name | Symbol |
|---|---|---|
| area | square meter | m 2 |
| volume | cubic meter | m 3 |
| speed, velocity | meter per second | m/s |
| acceleration | meter per second squared | m/s 2 |
| wave number | reciprocal meter | m ?1 |
| mass density | kilogram per cubic meter | kg/m 3 |
| specific volume | cubic meter per kilogram | m 3/kg |
| current density | ampere per square meter | A/m 2 |
| magnetic field strength | ampere per meter | A/m |
| amount-of-substance concentration | mol per cubic meter | mol/m 3 |
| luminance | candela per square meter | cd/m 2 |
| mass fraction | kilogram... |
TABLE OF CONTENTS 
