Common Metric Units
We use the Metric System (also called SI) for almost all scientific work. Common Metric (SI) Units include the following:
| Name | Long | Short |
|---|---|---|
| Acceleration | meter per second squared | m/s2 |
| Amount of substance | mole | mol |
| Angle | radian | rad |
| Angular Acceleration | radian per second squared | rad/s2 |
| Angular Velocity | radian per second | rad/s |
| Area | square meter | m2 |
| Density | kilogram per cubic meter | kg/m3 |
| Electrical Current | ampere | A |
| Energy | joule | J or N·m |
| Force | newton | N or kg·m/s2 |
| Frequency | hertz | Hz or 1/s |
| Impulse | newton-second | kg·m/s |
| Length | meter | m |
| Luminous intensity | candela | cd |
| Mass | kilogram | kg |
| Moment of a Force | newton-meter | N·m |
| Power | watt | W or J/s |
| Pressure | pascal | Pa or N/m2 |
| Stress | pascal | Pa or N/m2 |
| Temperature | kelvin (or degree Celsius) | K (or °C) |
| Time | second | s |
| Velocity | meter per second | m/s |
| Volume (solids) | cubic meter | m3 |
| Volume (liquids) | liter | L or 10-3 m3 |
| Work | joule | J or N·m |
Capital Letters?
Lowercase is used for unit names, even when the unit is named after a person. Examples:
- newton
- watt
- hertz
- pascal
Uppercase is used for the unit's symbol (abbreviation) when it is derived from a proper name. Examples:
- N for newton
- W for watt
- Hz for hertz
- Pa for pascal
Special rule for liters: as "l" looks like "1" we use "L".