Date: Thu, 16 Mar 2000 21:42:01 -0500 From: "Crist J. Clark" <cjc@cc942873-a.ewndsr1.nj.home.com> To: Mark Ovens <mark@dogma.freebsd-uk.eu.org> Cc: Greg Lehey <grog@lemis.com>, Brett Taylor <brett@peloton.runet.edu>, Paul Richards <paul@originative.co.uk>, chat@FreeBSD.ORG Subject: Re: Useful Metric Conversions Message-ID: <20000316214201.D64407@cc942873-a.ewndsr1.nj.home.com> In-Reply-To: <20000316234228.C248@parish>; from mark@dogma.freebsd-uk.eu.org on Thu, Mar 16, 2000 at 11:42:28PM %2B0000 References: <20000316182207.C235@parish> <Pine.BSF.4.10.10003161417340.57499-100000@peloton.runet.edu> <20000316215216.A248@parish> <20000316141306.C2841@mojave.worldwide.lemis.com> <20000316234228.C248@parish>
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On Thu, Mar 16, 2000 at 11:42:28PM +0000, Mark Ovens wrote: > On Thu, Mar 16, 2000 at 02:13:06PM -0800, Greg Lehey wrote: > > On Thursday, 16 March 2000 at 21:52:16 +0000, Mark Ovens wrote: > > > On Thu, Mar 16, 2000 at 02:18:29PM -0500, Brett Taylor wrote: > > >> Hi, > > >> > > >> On Thu, 16 Mar 2000, Mark Ovens wrote: > > >> > > >>> On Thu, Mar 16, 2000 at 02:10:59AM +0000, Paul Richards wrote: > > >> > > >>>>> 453.6 graham crackers = 1 pound cake > > >>>> > > >>>> I'm not getting that one at all? > > >>>> > > >>> > > >>> Neither do I. I didn't dream them up, I just posted them. > > >> > > >> 454 grams to the pound (roughly). > > > > > > Yes, I knew that. What I don't know is what "graham crackers" are, or > > > is it just word-play on gram? > > > > > >> Why you'd compare a mass to a weight is > > >> anyone's guess, but that's probably just the physics in me talking. :-) > > >> > > > > > > Both the imperial and metric systems mix up mass and weight. I was > > > always explained to me that this is because the average non-technical > > > person can't understand the difference; buting 1kg of sugar is easy to > > > grasp, but 9.81 Newtons? > > > > The metric system made a distinction between weight and mass right > > from the beginning. The gram was the unit of mass, > ^^^ > > is Depends. IIRC, some would say that the kilogram is the basic unit of mass. For a long time, some 1 kg reference mass sitting under some glass in France was _the_ kilogram. Now I think mass is defined as exactly so many carbon-12 atoms or something along those lines? Remember MKS (meters, kilograms, seconds) and CGS (centimeters, grams, seconds) as the different sets of units to make compound units in SI. e.g., 1 N = 1 kg m/s^2 1 dyne = 1 g cm/s^2 1 Joule = 1 kg m^2/s^2 1 erg = 1 g cm^2/s^2 MKS seemed to be the more "proper" ones. > > not weight; the > > unit of weight was the bary, which dropped out of use. > > > > In the SI system the Newton is the unit of weight, weight being the > force of gravity exerted on a mass. The Newton is the unit of force. The force required to accelerate on kilogram mass at one meter per second per second. "Weight" happens to be the force that the Earth's gravity imposes on a mass. I always remember the college professor who had been using American Engineering Units too long trying to convince us that there really was a g_c in, F = ma When using SI units, but it just happened to be unity. We never bought it. I've been dealing with an old FORTRAN code at work lately. All kinds of painful units, BTUs, ft/s, Rankine, lbm, lbf. -- Crist J. Clark cjclark@home.com To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-chat" in the body of the message
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