{"title":"Fundamentals in Measurement: Looking Out for Number 1","authors":"Richard Davis","doi":"10.1109/MIM.2023.10328673","DOIUrl":null,"url":null,"abstract":"The International System of Units (SI) [1] was inaugurated in 1960, following years of discussions interrupted by world wars. At that time, a consensus did not yet exist on whether the SI unit of plane angle, the radian (symbol: rad), should be treated as a base unit with its own dimension A, independent of all other base dimensions, or as a unit derived from the meter (m). Provisionally, either interpretation could be used as needed. Thirty-five years later, it was finally decided that the radian should be defined as a derived unit equal to 1. Mathematically, then, $1\\ \\text{rad} =1\\ \\mathrm{m}/\\mathrm{m}=1$. Reference [1] notes that some ambiguities have arisen from this choice. For instance, a general rule that “the unit symbol 1 or unit name ‘one’ are not explicitly shown” can be problematic. Therefore, rad can be used for clarity when helpful, i.e., rad can be written explicitly with the understanding that 1 rad = 1.","PeriodicalId":55025,"journal":{"name":"IEEE Instrumentation & Measurement Magazine","volume":" 20","pages":"5-11"},"PeriodicalIF":1.6000,"publicationDate":"2023-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"IEEE Instrumentation & Measurement Magazine","FirstCategoryId":"5","ListUrlMain":"https://doi.org/10.1109/MIM.2023.10328673","RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q3","JCRName":"ENGINEERING, ELECTRICAL & ELECTRONIC","Score":null,"Total":0}
引用次数: 0
Abstract
The International System of Units (SI) [1] was inaugurated in 1960, following years of discussions interrupted by world wars. At that time, a consensus did not yet exist on whether the SI unit of plane angle, the radian (symbol: rad), should be treated as a base unit with its own dimension A, independent of all other base dimensions, or as a unit derived from the meter (m). Provisionally, either interpretation could be used as needed. Thirty-five years later, it was finally decided that the radian should be defined as a derived unit equal to 1. Mathematically, then, $1\ \text{rad} =1\ \mathrm{m}/\mathrm{m}=1$. Reference [1] notes that some ambiguities have arisen from this choice. For instance, a general rule that “the unit symbol 1 or unit name ‘one’ are not explicitly shown” can be problematic. Therefore, rad can be used for clarity when helpful, i.e., rad can be written explicitly with the understanding that 1 rad = 1.
期刊介绍:
IEEE Instrumentation & Measurement Magazine is a bimonthly publication. It publishes in February, April, June, August, October, and December of each year. The magazine covers a wide variety of topics in instrumentation, measurement, and systems that measure or instrument equipment or other systems. The magazine has the goal of providing readable introductions and overviews of technology in instrumentation and measurement to a wide engineering audience. It does this through articles, tutorials, columns, and departments. Its goal is to cross disciplines to encourage further research and development in instrumentation and measurement.