Name: si and customary measurement systems
Uploaded: 2023-09-22T11:49:19.000Z
Duration: 1 min 27 s
Channel: JoVE

La longueur, la masse et le temps sont les grandeurs de base pour la mesure, et leurs unités sont appelées unités de base.
Les unités dérivées des unités de base sont appelées unités dérivées.
Les systèmes d’unités peuvent être classés dans le système international d’unités ou unités SI et le système d’unités coutumier des États-Unis.
Dans les unités SI, mètre, kilogramme et seconde sont les unités de base, tandis que dans le système d’unités habituel des États-Unis, pied, livre et seconde sont les unités de base.
Par exemple, l’unité de force SI est le newton, qui est une unité dérivée. Elle est définie comme la force nécessaire pour accélérer un kilogramme de masse à raison d’un mètre par seconde au carré.
Dans le système d’unités usuel des États-Unis, l’unité de masse est slug qui est une unité dérivée. Il est défini comme la quantité de matière accélérée d’un pied par seconde au carré lorsqu’elle est soumise à une force d’une livre.
Les unités d’un système peuvent être converties en celles d’un autre système à l’aide de facteurs de conversion.

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	<li>Hibbeler, R.C. (2016). Génie mécanique \u2012 Statique et dynamique. Hoboken, New Jersey : Pearson Prentice Hall. pages 7 à 8</li>
	<li>Bière, F.P. ; Johnston, E.R. ; Mazurek, D.F ; Cromwell, P.J. et Self, B.P. (2019). Mécanique vectorielle pour les ingénieurs \u2012 Statique et dynamique. New York : McGraw-Hill. pp 4 et 8</li>
	<li>Meriam, J.L. ; Kraige, L.G. et Bolton, J.N. (2020). Génie mécanique \u2012 Statique. Hoboken, New Jersey : John Wiley. pages 7 et 8</li>
</ol>

unités de mesure

Units of Measurement

L'ingénierie mécanique est l'une des plus anciennes branches de l'ingénierie. Elle concerne la conception, l'analyse et la fabrication de machines et de systèmes mécaniques. Pour garantir des calculs précis et exacts, des unités de mesure sont utilisées. Elles fournissent un système standard d'expression et de comparaison des quantités physiques. Il existe différents systèmes de mesure historiques bien connus, tels que le système babylonien, le système romain, le système égyptien, le système olympien, le système britannique et le système de la vallée de l'Indus. Le Système international d'unités (SI) est le standard de mesure universellement reconnu utilisé en ingénierie mécanique. Il est basé sur des unités de base fondamentales qui peuvent être combinées pour exprimer toutes les autres quantités physiques. Les unités dérivées des unités de base sont appelées unités dérivées. Par exemple, l'unité SI de la force est le Newton, qui est une unité dérivée. Elle est définie comme la force nécessaire pour accélérer un kilogramme de masse à une vitesse d'un mètre par seconde carrée. Différents systèmes d'unités de mesure sont utilisés à travers le monde. En plus du Système international d'unités (SI), le système de mesures américain est un autre système couramment utilisé. Dans le système de mesures américain, les unités de base sont le pied, la livre et la seconde. L'unité de longueur est le pied, l'unité de masse est la livre et l'unité de temps est la seconde. Dans le système de mesures américain, l'unité de masse est le slug, une unité dérivée. Elle est définie comme la quantité de matière accélérée d'un pied par seconde carrée lorsqu'elle est soumise à une force d'une livre. Étant donné que de nombreux pays continuent d'utiliser le système de mesures américain, une relation entre les différentes unités comparables a également été développée. Par exemple, un mètre équivaut à 3 280 pieds. Les unités dérivées diffèrent également d'un ensemble de normes à l'autre. Par exemple, le système SI utilise le Newton comme unité de force, tandis que le système de mesures américain utilise la livre. Les unités de mesure sont essentielles en ingénierie mécanique car elles permettent des mesures précises et exactes. Les ingénieurs utilisent ces unités pour concevoir et analyser des machines et des systèmes mécaniques, estimer les charges, les contraintes et les déformations des composants mécaniques, ainsi que pour prédire le comportement des machines dans des conditions de fonctionnement différentes.

Unités de mesure

Le génie mécanique est l’une des plus anciennes branches de l’ingénierie. Il s’occupe de la conception, de l’analyse et de la fabrication de machines et de ...

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si and customary measurement systems

Mechanical engineering depends on units of measurement for precise and accurate calculations. These units give engineers a standard way to express and compare physical quantities. They are essential when designing and analyzing machines and mechanical systems.

Many historical measurement systems have been used over time. Examples include the Babylonian system, the Roman system, the Egyptian system, the Olympian system, the British system, and the Indus Valley system. Today, the International System of Units, or SI, is the widely recognized standard used in mechanical engineering.

The SI system is built from base units. These base units can be combined to describe other physical quantities, which are called derived units. For example, the SI unit of force is the Newton. One Newton is the force needed to accelerate one kilogram of mass at one meter per second squared.

Another common system is the U.S. Customary System of Units. Its base units are the foot, the pound, and the second. In this system, length is measured in feet, mass is measured in pounds, and time is measured in seconds. The slug is the derived unit used for mass in this system, and it is defined by the amount of matter accelerated by one foot per second squared under a force of one pound.

Because many countries still use the U.S. Customary System, conversion relationships are important. For example, one meter equals 3,280 feet. Derived units also differ between systems. SI uses the Newton for force, while the U.S. Customary System uses the pound. Engineers use these units to estimate loads, stresses, and deformations, and to predict how machines behave under different operating conditions.

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SI and Customary Measurement Systems

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