>From: [EMAIL PROTECTED] (Joseph B. Reid) >Reply-To: [EMAIL PROTECTED] >To: "U.S. Metric Association" <[EMAIL PROTECTED]> >Subject: [USMA:16976] Re: Does science work with imperial at all?? >Date: Sun, 30 Dec 2001 21:09:19 -0500 > >Han wrote in USMA 16946: > > >British Gravitational has this unit of force (comparable with the kgf): > > > >pound force (lbf or lb) > > > >a traditional unit of force. Traditional measuring systems did not > >distinguish between force and mass units. A force of one pound is simply >the > >gravitational force experienced at the Earth's surface by a mass of one > >pound. To compute this force, we multiply the mass by the acceleration of > >gravity, following Newton's law F = ma. Since one pound of mass is 0.453 >592 > >kilograms and the acceleration of gravity averages 9.806 65 meters per > >second per second at the surface of the Earth, one pound force equals the > >product of these two numbers, 4.448 221 615 newtons. The symbol lbf >should > >be used for the pound force to distinguish it from the pound of mass > > > >British Absolute. It has a pure unit of force, just as SI has the newton. >It > >is used far less than the lbf. > > > >poundal (pdl or pl) > > >The poundal was the British physicists unit. British engineers regard the >pound-force as their base unit. The Royal Aircraft Establishment in 1940 >used the "slug" as their unit of mass. It was equal to 32.2 pounds-mass. >In that way F = m.a, where F is in poouns-force, m is in slugs, and a is in >feet per second squared. > >Joseph B.Reid >17 Glebe Road West >Toronto M5P 1C8 TEL. 416-486-6071 > GB is strange, so many english physicians contributed to SI and GB rejected them! _________________________________________________________________ Testen Sie MSN Messenger f�r Ihren Online-Chat mit Freunden: http://messenger.msn.de
