Some fields of
engineering
Engineering is the use of scientific principles to design and build machines, structures, and other items, including bridges, tunnels, roads, vehicles, and buildings. The discipline of engineering encompasses a broad range of more speciali ...
in the United States use a system of measurement of physical quantities known as the English Engineering Units. Despite its name, the system is based on
United States customary units of measure; it is not used in England.
A similar system, termed British Engineering Units by Halliday and Resnick (1974), was a system that used the
slug as the unit of mass, and in which Newton's law retains the form ''F=ma''. Modern British engineering practice has used
SI base units since at least the late 1970s.
Definition
The English Engineering Units is a system of
consistent units used in the United States. The set is defined by the following units,
with a comparison of
their definitive conversions to their
International System of Units counterparts.
Units for other physical quantities are derived from this set as needed.
In English Engineering Units, the pound-mass and the pound-force are distinct base units, and
Newton's Second Law of Motion takes the form ''F= ma/g
c'', where ''g''
c=32.174lb·ft/(lbf·s
2).
History and etymology
The term
English units
English units are the units of measurement used in England up to 1826 (when they were replaced by Imperial units), which evolved as a combination of the Anglo-Saxon and Roman systems of units. Various standards have applied to English units at ...
strictly refers to the system used in England until 1826, when it was replaced by (more rigorously defined)
Imperial units
The imperial system of units, imperial system or imperial units (also known as British Imperial or Exchequer Standards of 1826) is the system of units first defined in the British Weights and Measures Act 1824 and continued to be developed th ...
. The United States continued to use the older definitions until the
Mendenhall Order
The Mendenhall Order marked a decision to change the fundamental standards of length and mass of the United States from the customary standards based on those of England to metric standards. It was issued on April 5, 1893, by Thomas Corwin Mend ...
of 1893, which established the United States customary units. Nevertheless, the term "English units" persisted in common speech and was adapted as "English engineering units" but these are based on US customary units rather than the pre-1826 English system.
See also
*
Imperial and US customary measurement systems
The imperial and US customary measurement systems are both derived from an earlier English system of measurement which in turn can be traced back to Ancient Roman units of measurement, and Carolingian and Saxon units of measure.
The US Cust ...
References
Notes
{{United States Customary Units
Customary units of measurement
Customary units of measurement in the United States