It is a pity that the BIPM could not reserve a symbol without a formal definition for the year to ensure that the symbol is not used for anything else. A note would explain that the user of the symbol should means what was meant by a "year" - a financial house would use the symbol when talking about calendar years while an astronomer would attach a different meaning to the symbol.
-----Original Message----- From: [email protected] [mailto:[email protected]] On Behalf Of James R. Frysinger Sent: 02 April 2010 14:34 To: U.S. Metric Association Cc: U.S. Metric Association Subject: [USMA:47020] Re: Correct me if I'm wrong... The second is an SI unit. Minutes, hours, and days are not -- however, they are accepted for use with the SI. So m/s is an SI unit and km/h is not. However, both are perfectly acceptable in the eyes of the CGPM, CIPM, BIPM, et al. The unit cm/min is also acceptable for use. It is very, very nearly equivalent to the non-SI unit furlong per fortnight. Jim Stephen Davis wrote: > ....I'm not sure on this one, so I probably am wrong but, aren't hours, > minutes and seconds accepted as SI units anyway? > > If this is the case, then there's little problem with describing a > distance as km/h surely? > > > ----- Original Message ----- > *From:* John Frewen-Lord <mailto:[email protected]> > *To:* U.S. Metric Association <mailto:[email protected]> > *Sent:* Thursday, April 01, 2010 8:52 PM > *Subject:* [USMA:47013] Re: FW: Special Employee Advisory: Message > from Joe Boardman > > Dear all: > > It's not often I agree with Stephen Humphreys, but on this occasion > I think he's right. I once wrote an article for the UKMA > Newsletter, suggesting that we might need to make more use of what I > call the 'vernacular' in our use of SI for the everyday person. > That using metric must become as natural as it seems for people > brought up on imperial/USC to continue using those units. Hence I > suggested that we could describe our height as 'one-seventy-eight' > (1.78 m or 178 cm - your choice), our weight as 75 kaygees (I really > hate kaygees, but recognise that it makes using metric less > intimidating or clinical), our speed as 130 'kays' (or klicks') and > so on. > > When it comes to km/h, that is what the entire world uses for > measuring speed, rightly or wrongly. Maybe it is 'wrong', but are > you going to change the entire world in this regard? As the US > hardly uses metric in the everyday sense (agreed that there is a lot > of hidden metric), then there is little chance the rest of the world > is going to take much notice if the US starts pontificating that we > should be using m/s rather than km/h, and even less chance that the > rest of the world is going to actually change. > > Regardless of what measuring units we use, most of us relate to them > in a comparative or relative sense only, not in absolute terms. We > know that we take a size 8 shoe, or that we (at least the ladies > do!) fit into a size 14 dress, and so on, without ever knowing > exactly what those numbers mean. And we currently measure speed on > that basis. We know (at least those of us living in those > countries which measure our speed in km/h, which is virtually the > entire world USA and UK excepted) that 50 km/h is a typical urban > speed, that 80-100 km/h is a typical two lane highway speed and that > 100-130 km/h is a typical freeway/motorway speed. We don't need to > actually visualise how many metres per second that represents, and > even if we did, we probably wouldn't be able to make practical use > of it. On the other hand, when planning journeys, a typical > suburban/rural average speed is say 60 km/h, which is 1 km per > minute. So a 20 km journey will take 20 minutes. On longer > journeys, where we might measure our time in hours, we might be able > to average 100 km/h, so a 400 km journey will take 4 hours. Km/h > allows these calculations to be made; m/s doesn't. > > I think if we want the general populace to embrace metric, we have > to accept such 'vernacular' in its use. The clinically correct > stuff we can reserve for professional usage. Oh, and as a surveyor > working in the UK, I can assure everyone that I was indeed > 'clinically correct' in my usage of SI in my professional work. For > everyday usage, I find I am quite happy to 'lighten up' and use the > 'vernacular'. > > John F-L > > > > ----- Original Message ----- > *From:* Stephen Humphreys <mailto:[email protected]> > *To:* U.S. Metric Association <mailto:[email protected]> > *Sent:* Thursday, April 01, 2010 8:13 PM > *Subject:* [USMA:47012] Re: FW: Special Employee Advisory: > Message from Joe Boardman > > I fully understand where you are coming from but even in 'fully' > metric countries km/h is used. I cannot see that changing but > furthermore I would not recommend pushing clinical use of si on > non metric people. Remember that in effect you have to 'sell' > this change so being critical about specifics should really be > low on your priorities. Of course this just my opinion > > > From: [email protected] > > Subject: Re: [USMA:47008] Re: FW: Special Employee Advisory: > Message from Joe Boardman > > To: [email protected]; [email protected] > > Date: Wed, 31 Mar 2010 10:04:08 -0500 > > > > Stephen, > > > > The point you always seem to miss is that the question is not > the traditional units habitually used since the 18 century or > earlier, but the best units from SI for use in the future. > > > > ---- Original message ---- > > >Date: Wed, 31 Mar 2010 09:07:22 +0000 > > >From: Stephen Humphreys <[email protected]> > > >Subject: [USMA:47008] Re: FW: Special Employee Advisory: > Message from Joe Boardman > > >To: "U.S. Metric Association" <[email protected]> > > > > > > I admire your scientific brain Martin ;-) but I'll > > > bet you a large sum of money that most (British) > > > people would quickly understand 95 mph and have a > > > 'feel' for what that looks like over "50 m/s based > > > upon some maths" even though what you say > > > technically makes a lot of sence. > > > > > > Of course, 'practice' often proves things and if you > > > ever hear one of the bowlers/batters for the England > > > and Wales side talking about fast-bowlers and > > > spin-bowlers then you note they will always use > > > mph. In fact my quote below about Flintoff came > > > from an Aussie cricketer(!). Note sure whether the > > > aussie chap in question used mph because they knew > > > it was SkySports interviewing them or not, however > > > whenever I have heard a feed from Australian criket > > > games I have often heard both mph and km/h > > > (admittedly more km/h from Australian broadcasts > > > than mph). Incidentally they refer to km/h as > > > 'kays' - eg "He bowled that one at 130 kays". > > > > > > > > > ------------------------------------------------ > > > > > > From: [email protected] > > > To: [email protected] > > > Subject: [USMA:47007] Re: FW: Special Employee > > > Advisory: Message from Joe Boardman > > > Date: Wed, 31 Mar 2010 06:36:44 +0100 > > > > > > On the other hand being told that the ball is coming > > > at you at 50 m/s and knowing that the pitch is just > > > 20 m long tells you that you have 0.4 s to work out > > > what to do with the ball. (A little less because you > > > are in front of the wickets) > > >.. > > ------------------------------------------------------------------------ > Do you have a story that started on Hotmail? Tell us now > <http://clk.atdmt.com/UKM/go/195013117/direct/01/> -- James R. Frysinger 632 Stony Point Mountain Road Doyle, TN 38559-3030 (C) 931.212.0267 (H) 931.657.3107 (F) 931.657.3108
