Common and technical meaning
Dear Covers:
Here's my $0.01 to this standard versus norm. As I went through the thread, I found myself agreeing with both Markasmith and Graeme. Each point of view is a valid one.
However, to go a step further, definitions must be precise. There can be no room for any vagueness. By appealing to the French (as the "authoritative" version, or what might be called the "standard") as opposed to the English translation, one is still left, it appears, with the problem of choosing between the commonly accepted meanings of 'norm' and 'standard'
in English.
So, I thought the following might help by providing a different perspective. Before Newton came along, the terms mass and force were certainly being used in the English language. A massive object means one that has a higher mass. A massive rally means a huge, or a very large, rally, say in the stock market. Newton gave a precise meaning to these two terms. Of course, Newton wrote in Latin and we are therefore relying on the English translation by Andrew Motte.
The following is from the opening paragraph of his Principia (can be found in most bookstores). Newton defines mass as the product of the density of the body times its volume. To quote, "Thus, air of double density, in a double space, is quadruple in quantity; in a triple space is sextuple in quantity. The same thing is to be understood of snow, and fine dust, or powders, that are condensed by compression or liquefaction; and aof all boides that are by any causes whatever differently condensed. I have no regards in this place to a medium, if any such there is, that freely pervades the interstices between the parts of bodies. It is this quantity that I mean hereafter everywhere under the name of body or mass. And the same is known by the weight of each body; for its is proportional to the weight, as I have found by experiments on pendulums, very accurately made, which shall be shown hereafter."
This is a remarkable definition. Newton tells us exactly what he means by the term mass. His definition includes many different types of bodies, including porous bodies. He also tells us how to measure mass. This is done by the process of weighing (using a simple balance, I presume) which humans had been using long before Newton. He also tells us that he is no arm chair theoretician. He has verified his statements by actual experiments with pendulums.
Later, Newton defines what he means by force and enunciates his three force laws. It is also of interest to note that Newton does not talk about the "work" done by a force. This idea was conceived by James Watt, as noted in another thread. (Technology and the Olympic Gold, see also One Ton of a Man and the post Walking and Losing Weight).
My point? Nothing was lost in the translation from Latin to English. Mass is still density times the volume. There is no vagueness. This is indeed a physics lesson, like someone said in a response to the thread Technology and the Olympic Gold. :mg:
If I am permitted to continue, yes, I think, we must understand the meaning of "work" in a much broader context. Not, how "work" as defined in physics can be related to "work" as done by computers, or robots, but how all this ultimately relates to "money". This is what James Watt and his business partner Matthew Boulton were trying to do. They tried to compare the work done by a steam engine with the work done by a horse. What they were really interested in was understanding
how much money can be saved by replacing the horse by the steam engine. This was the marketing strategy. The switch from horses to steam engines, in the 18th century, was motivated by the desire to increase profits. Of course, many new applications for steam engines, not imagined by James Watt and his partner, followed soon after.
This also, ultimately, and in my humble opinion, is what can be gained by appealing to the idea of a "work function" as conceived by Einstein, when he developed his photoelectricity law. Einstein takes the idea of "work", or what is the same as "energy" in physics, for granted. The idea of work and energy eluded the genius of men like Galileo and Newton (page 531, in Physics, Volume 1, by David Halliday and Robert Resnick, 1966 edition). These ideas could be developed only after James Watt's steam engine came along and vigorous studies on the nature of heat began. Following Watt, Sadi Carnot and Clausius made notable contributions in the first half of the 19th century. Carnot's analysis of heat engines was only motivated by economic considerations. Carnot was trying to determine the
maximum amount of "work" (now given clear meaning by Watt) that could be done by an engine with the
minimum expenditure of energy in the form of heat (produced by burning coal, which costs money). Finally, Joule's experiments (and other related findings, in the 1850s) established the law of conservation of energy. Einstein invokes this law to formulate the idea of a work function W, as described in the simple statement, K = hf - W. More generally, y = hx - W.
Charmed
P. S. I was hoping to discuss the work function idea with some more examples soon, from the business world. The recent
Google IPO provides an opportunity, as does some recent data on Toyota Motor Company (WSJ front page article, August 4, 2004). If there is a receptive audience, I would be happy to post them in the new Forum, Philosophy, Gurus, Controversy, etc. that Marc has created.
