The international system of units is practically legal in all the countries; but some countries as United States, United Kingdom and the old colonies of US and UK refuse this system.
United States customary units are a system of measurements commonly used in the United States.
The United States customary system (also called American system or, sometimes, "English units") is the most commonly used system of measurement in the United States.
Three nations have not officially adopted the International System of Units as their primary or sole system of measurement: Burma, Liberia, and the United States.
Usually people use the metric system, some (like people of the United States) use the English system.
The system of units used in the United States is called the United States customary units or US customary units. This system includes units such as feet, pounds, and gallons.
The Imperial system of measurements, originally used in England.
Although it is familiar with the International system, the United States uses the English system of units.
The units used to measure the work done in a given task are joules (J) in the International System of Units (SI) and foot-pounds (ft-lb) in the Imperial system.
Units such as the meter, kilogram, liter, and Celsius are part of both the United States customary system and the metric system.
The International System of Units has standard units for all types of measurements.Unfortunately some countries as United States, Canada, United Kingdom and colonies doesn't recognize the SI.
The English system is a system of units of measurement commonly used in the United States, which includes units such as inches, feet, pounds, and gallons. It is distinct from the metric system used in most other countries.
The units of diffusivity are typically square meters per second (m2/s) in the International System of Units (SI). Diffusivity can be determined in a given system through experimental measurements or theoretical calculations based on factors such as temperature, pressure, and the properties of the substances involved.
cuz the united states is a pig headed 'democratic' state which thinks it is always right even though it is mostly wrong.
US customary units
The international system of units is practically legal in all the countries; but some countries as United States, United Kingdom and the old colonies of US and UK refuse this system.
The three systems of units in physics are the International System of Units (SI), the British Imperial System, and the US Customary System. The SI system is the most widely used and accepted system in the scientific community, while the British Imperial and US Customary systems are primarily used in the United Kingdom and the United States, respectively.