# TABULA/samples/units

## What is meant by the word: units ?

The units of a given physical quantity is a standardized description of what the quantity is measured in.

Thus, if discussing distance, it is not enough for us to write down the number: 2. Our audience needs to know: two – of what?

• two metres?
• two centimetres?
• two kilometres?

If we mean two kilometres, there is a standard way of writing this down: 2 km

• This standard is known as Système-Internationale (SI); and the units (km) are called SI-units.
• Other standards are possible, such as Imperial Units (the next most popular standard worldwide).

## SI Units and TABULA

TABULA works internally with SI-units. It can handle units in other standards of measurement, but only if such units are defined in terms of SI-units. Thus…

• one mile (1 mi) = 1.60934 km
• one pound (1 lb) = 0.45359237 kg

(These units are pre-defined in TABULA, along with hundreds of others. You don't need to look them up in a reference book and define them to TABULA yourself.)

OBSERVATION: units is a singular noun in this context. It is short for: scientific units, and is not the plural of unit.

(The word unit[y] means one-ness, referring to the value: 1.

Examples of units are:

 kg mass kilogram mph speed miles-per-hour mi/h speed miles-per-hour m/s speed metres-per-second m·s⁻² acceleration metres-per-second-every-second; metres-per-second-squared (correct SI units)