Fully agree. Soon after pressing the SEND button I realized how wrong I was. I hope everyone received the table and my apology.
The definition: A *joule per meter* (J/m) is a metric unit of force. In mechanics, a *joule* is defined as the work done by a force of one newton acting to move an object through a distance of one *meter* in the direction in which the force is applied (1 J = 1 N. m). Therefore, *joule per meter* is equal to newton. Stan On Tue, Aug 9, 2016 at 10:08 AM, <jmsteele9...@sbcglobal.net> wrote: > Respectfully disagree, and I earlier posited that it was energy per unit > length of the bolt. In electrical and magnetic fields, line sources are > frequently assumed as an approximation. Of course, real sources would tend > to have a diameter, but for distances large compared to diameter, but small > compared to length, a line source is a convenient approximation. You can > then go on to determine the energy stored in space around the line source > or power radiated from it and it will have dimensions of J/m, W/m or for > long florescent tubes, lumens per meter. > > Now I will admit that lightning bolts aren't very straight and the > usefulness of this measure in this situation isn't very apparent to me. > However, I can think of cases where it is very useful, long, straight > wires, lighting, etc. > > > ------------------------------ > *From:* Stanislav Jakuba <jakub...@gmail.com> > *To:* Bill Hooper <billhoope...@gmail.com>; U.S. Metric Association < > usma@colostate.edu> > *Sent:* Tuesday, August 9, 2016 9:49 AM > *Subject:* [USMA 291] Re: Puzzled > > MJ/m: > Well, I guess, there will not be the consensus. My take: The unit J/m > refers to a non-existing quantity and for that and other reasons it cannot > exist. The quantity "length" cannot have energy, be it in mm, m, or Mm. Nor > can an area (m2) contain energy. The sensible units are: energy per volume > (J/m3), or energy per mass (J/kg), and, of course, energy per time which we > call the watt (W). > > The question is - how seriously should we take a scientific information > that repeatedly refers to a non-existing SI unit? What more can USMA do to > help out scientist get SI literate? Particularly governmental as has been > the case here. > > Stan > > On Sat, Aug 6, 2016 at 11:57 AM, Bill Hooper <billhoope...@gmail.com> > wrote: > > > > On my iPad from Cypress Village, Jacksonville, FL > > On Aug 5, 2016, at 12:08 PM, Stanislav Jakuba <jakub...@gmail.com> wrote: > > > > > Once more: What is J/m? > > How about reaching a consensus? ☺ > > Stan > > > > I think the "m" in "J/m" refers to the length of the lightning stroke . It > measures the energy of each meter of length of the stroke. It's joules of > energy per meter of length of the stroke. > > > > _______________________________________________ > USMA mailing list > USMA@colostate.edu > https://lists.colostate.edu/cgi-bin/mailman/listinfo/usma > > >
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