Editing Weight (section)

===Gravitational definition===
The most common definition of weight found in introductory physics textbooks defines weight as the force exerted on a body by gravity.<ref name="Morrison"/><ref name="Galili-Lehavi"/> This is often expressed in the formula {{nowrap|1=''W'' = ''mg''}}, where ''W'' is the weight, ''m'' the mass of the object, and ''g'' [[gravitational acceleration]].

In 1901, the 3rd [[General Conference on Weights and Measures]] (CGPM) established this as their official definition of ''weight'':
{{blockquote|The word ''weight'' denotes a quantity of the same nature{{#tag:ref
 |The phrase "quantity of the same nature" is a literal translation of the [[French (language)|French]] phrase ''grandeur de la même nature''. Although this is an authorized translation, VIM 3 of the [[International Bureau of Weights and Measures]] recommends translating ''grandeurs de même nature'' as ''quantities of the same kind''.<ref>{{cite book
 |author=Working Group 2 of the Joint Committee for Guides in Metrology (JCGM/WG 2)
 |title=International vocabulary of metrology – Basic and general concepts and associated terms (VIM) – Vocabulaire international de métrologie – Concepts fondamentaux et généraux et termes associés (VIM)
 |url=http://www.bipm.org/utils/common/documents/jcgm/JCGM_200_2008.pdf
 |date=2008 |edition=3rd |type=JCGM 200:2008 |publisher=[[BIPM]]
 |at=Note 3 to Section 1.2
 |language=en, fr
}}</ref>|group=Note
}} as a ''force'': the weight of a body is the product of its mass and the acceleration due to gravity.
|Resolution 2 of the 3rd General Conference on Weights and Measures<ref name="3rdCGPM"/><ref name="NIST330">{{Cite book |editor1=David B. Newell |editor2=Eite Tiesinga |title=The International System of Units (SI) |url=https://nvlpubs.nist.gov/nistpubs/SpecialPublications/NIST.SP.330-2019.pdf |publisher=[[National Institute of Standards and Technology|NIST]] |location=Gaithersburg, MD |date=2019|edition=NIST Special publication 330, 2019 |page=46 }}</ref>}}
This resolution defines weight as a vector, since force is a vector quantity. However, some textbooks also take weight to be a scalar by defining:
{{blockquote|The weight ''W'' of a body is equal to the magnitude ''F<sub>g</sub>'' of the gravitational force on the body.<ref name="Halliday 2007 95">{{cite book |title=Fundamentals of Physics |volume=1 |first1=David |last1=Halliday |first2=Robert |last2=Resnick |first3=Jearl |last3=Walker |publisher= Wiley |date=2007 |edition=8th |page=95 |isbn= 978-0-470-04473-5}}</ref>}}

The gravitational acceleration varies from place to place. Sometimes, it is simply taken to have a [[standard gravity|standard value]] of {{nowrap|9.80665 m/s<sup>2</sup>}}, which gives the [[standard weight]].<ref name="3rdCGPM">{{cite web
 |url=http://www.bipm.org/en/CGPM/db/3/2/
 |title=Resolution of the 3rd meeting of the CGPM (1901)
 |publisher=BIPM
}}</ref>

The force whose magnitude is equal to ''mg'' newtons is also known as the '''m kilogram weight''' (which term is abbreviated to '''kg-wt''')<ref>Chester, W. Mechanics. George Allen & Unwin. London. 1979. {{ISBN|0-04-510059-4}}. Section 3.2 at page 83.</ref>