Kilopond
Physical unit | |
---|---|
Unit name | Kilopond |
Unit symbol | |
Physical quantity (s) | force |
Formula symbol | |
dimension | |
system | Technical measurement system |
In SI units | , |
In CGS units | |
Named after | Latin pondus , 'weight' |
The kilopond (from Latin pondus , 'weight') is an outdated, non- SI -conforming unit of force . It was a basic unit of the technical system of measurement . The kilopond has been inadmissible by law in Germany since January 1, 1978 for specifying the force and has been replaced by the newton .
A kilopond is the force exerted by the gravitational acceleration on the earth's surface on a mass of one kilogram . The value of the standard acceleration is used here. It follows:
- .
As with the kilogram, the base unit is defined as a thousand times the apparent base unit Pond , which corresponds to the weight of one gram . Decimal multiples and parts are not formed from the unit kilopond, but from the unit pond. One example is the megapond, which corresponds to a million pond or one thousand kilopond. This unit was used, for example, for the axle load of steam locomotives or the load level of hoists in construction.
A kilopond should (when it was introduced) be the force exerted by the acceleration of gravity on the earth's surface on one cubic decimeter of water (of the highest density , i.e. at approx. 4 ° Celsius). Since gravity is location-dependent, sea level and 45 degrees latitude were also set. Later the standard acceleration of fall was used, which was laid down at the third general conference on Weights and Measures .
The kilopond was originally referred to as the kilogram in the now outdated technical measurement system, and also as the force kilogram (kg, kg ^{*} , kg _{p} , kg _{f} , kgf) to distinguish it from the “mass kilogram ” of the physical CGS system . ^{}_{}_{}
Problems of definition
A mass of 1 kg experiences an average weight of 1 kp on earth at sea level . Colloquially, the mass of a body is often incorrectly referred to as "weight" and kilograms are practically equated with kilopond. Since the acceleration due to gravity differs slightly from place to place, the weight force on 1 kg is usually not exactly 1 kp.
Some types of scales (e.g. spring scales ) do not measure the mass but the weight exerted by a mass. They are still scaled in kilograms . Without calibration , the reading at different places on earth can vary by up to approx. One percent solely due to the local acceleration due to gravity.
With the introduction of the international SI system of units in 1960, the kilopond unit of force was replaced by the newton unit, which among other things prevents confusion between mass and weight, is much more reproducible and, above all, is embedded in a comprehensive concept for units.
See also
Individual evidence
- ^ ^{A } ^{b} Paul Dobrinski, Gunter Krakau, Anselm Vogel: Physics for engineers . Springer, 2003, ISBN 3-519-46501-9 , pp. 690 ( limited preview in Google Book search).
- ^ Text of the implementing ordinance to the law on units in metrology of June 26, 1970 , page 988
- ^ Paul Profos, Tilo Pfeifer: Handbook of industrial measurement technology. Oldenbourg, Munich 1994, ISBN 3-486-22592-8 , p. 626.