On 2006 Jan 7 , at 7:55 PM, Pat Naughtin wrote:
In the year 1960, or perhaps 1956. My copy of the document titled "The International system of Units (SI)" (7th ed.) published by BIPM states in a table headed "derived units" on page 114 that the unit of "work, energy and quantity heat" is the joule, with symbol "J" and equivalent to the "N.m". The table if part of Resolution 12 of the 11th CGPM in 1960. However, there is an indication that this same table was part of Resolution 3 of the CIPM in 1956 which contains a recommendation concerning the units to be used in SI. That is the same table as was adopted by the CGPM. (In actual fact, the table is only shown once in the documents I have. At the place where the table would be in the 1956 resolution there is just a note indicating that this resolution contained the same table as the other resolution.) So, the answer may depend on what Pat means by "introduced". The joule was first MENTIONED (in a recommendation) in 1956, but was not officially ADOPTED as part of the SI until 1960. There are even earlier recommendations that SI be built on the foundation of the old MKS system which had been in use for a number of years before. The MKS system unit for work and energy was the joule. Pat is correct in assuming the newton (N) was introduced about the same time. That unit is also in the table referred to above (as well as in the MKS system alluded to). Regards, Bill Hooper Fernandina Beach, Florida, USA ~~~~~~~~~~~~~~~~~~~ Go Metric, America ! ~~~~~~~~~~~~~~~~~~~ |
