Article Review: Mohr & Phillips 11BBz (2015d)
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Title: Article Review: Mohr & Phillips 11BBz (2015d) Reviewer: John Volan Review Date: 120Az (2026d) Reviewed Article: Dimensionless Units in the SI, Peter J. Mohr, William D. Phillips (National Institute of Standards and Technology), 11BB-05-24z (2015-05-28d) Subject: Angular mechanics and other in SI (and Primel) This article review was adapted from a series of posts in the Article Reviews about Angular Units thread on the DozensOnline at tapatalk. The reviewed article considers certain types of quantities that are treated as “dimensionless” by the International System of Units (SI), in particular angular quantities, but makes the argument that these ought to be treated as having first-class dimension, with units that are more than just pure dimensionless numbers. It expands on this to examine the role of true angular dimension in the various quantities of angular mechanics. One important conclusion is that the radian, and not the turn or cycle, is the only possible “coherent” unit of angle. The article review strengthens the argument by introducing a notational style that allows symbols in formulas of natural law to default to the SI “dimensionless” interpretation, but marks them with diacritics when they incorporate “true⋅angle” dimensions. It also uses the same diacritics to mark “complete” versions of trigonometric and other transcendental functions that take “true⋅angle” inputs or outputs; this allows the original unmarked versions of those functions to default to SI's “pure math” interpretation working on dimensionless quantities. Throughout, the review uses units from the Primel metrology in examples to demonstrate and clarify these principles, contrasting them with the difficulties caused by SI’s units. This discussion is continued in Article Review: Mohr et al 1206z (2022d) |
