This is my reply to a 2010 post from Hon Wai Lau concerning the input of units:
https://moodle.org/mod/forum/discuss.php?d=155989#p699110
Hi Hon,
In your example for the unit of the specific heat capacity, J K^(-1) kg^(-1), the ^ and ( ) are not necessary, i.e. the the unit could be written simply as J K-1 kg-1.
Since the minus sign and numbers are used only for raising base units to a power, they can be implied without creating confusion.
The space can be used for multiplication because it is simple and complies with SI, the / for division because it is common and also complies with SI, and the ( ) for when they are needed such as in W/(m K) for thermal conductivity. The ^ is not required.
Your examples:
| Quantity | Current units | Proposed units |
|---|---|---|
| Length / Displacement | m | m |
| Time | s | s |
| Mass | kg | kg |
| Velocity | m/s | m/s |
| Acceleration | m/s^2 | m/s2 |
| Momentum | kg m/s | kg m/s |
| Force | N | N |
| Energy | J | J |
| Power | W | W |
| Angle / Phase | rad | rad |
| Angular velocity | rad/s | rad/s |
| Angular acceleration | rad/s^2 | rad/s2 |
| Angular momentum | kg m^2/s | kg m2/s |
| Torque | N m | N m |
| Frequency | Hz | Hz |
| Wave number | m^(-1) | m-1 |
| Intensity | W/m^2 | W/m2 |
| Soound intensity level | dB | dB |
| Temperature | K | K |
| Pressure | Pa | Pa |
| Volume | m^3 | m3 |
| Area | m^2 | m2 |
| Density | kg/m^3 | kg/m3 |
| Specific latent heat | J/kg | J/kg |
| Specific heat capacity | J kg^(-1) K^(-1) | J kg-1 K-1 |
| Heat capacity | J/K | J/K |
| Entropy | J/K | J/K |