Terry Simpson wrote in USMA 22953:
Joseph B. ReidDoes Terry mean that the units that I listed in USMA 22931 ceased being metric when SI was defined? They indisputably were once "metric"I don't know about the past. One of my criticisms of the SI brochure is that it embeds the current rules within superceded rules. I am trying to find out how things are defined *now* so that I can use correct current terminology. I need to provide advice that it true and applicable for the designs of today.I read: "the International System of Units (SI), which is the modern form of the metric system." and I conclude: 1. SI unit = unit of the 'modern form of the metric system' (we appear to agree about this). 2. Non-SI unit = not a unit of the 'modern form of the metric system' (we do not appear to agree about this). Am I wrong in my second conclusion? Thank you for bearing with me on this. I appreciate it.
Yo9u are wrong See Tables 6, 7, and 8 of the "The International System of Units".
Table 6. Non-SI units accepted for use with the Intenational System
Table 7. Non-SIunits accepted for use with the International system, whose values in SI units are obtained experimentally.
Table 8. Other non-SI units currently accepted for use with the International System..
It is the units of Tables 9 and 9 that should be avoided, although many people still use them.
Table 9. Derived CGS units with special names
Table 10. Examples of other non-SI units
