Come on, Peoples! Work is DEFINED in Newtonian mechanics as being done "when a force moves its point of application". Thass all - and plenty enuff! So you lift a box up to a shelf - you doing work, as defined by Isaac, the Laborers Union and most Plain Folks. You put a whiskey jigger on a pool table - it and the table move , a very leetle bit, and work be done by gravity.
Railroad lines represent useful constraints to freight cars. Thanks to them the car becomes an "object that moves in predestinate grooves"! The car is subject to acceleration due to all forces acting on it, but the rails try to keep it from cross track motion. They does their best - to the extent that they are capable. You may generalize the technical terms " force", "work" and "constraint " as far as you like. After all, they had meaning in language long before they were "defined" by Newton and La Grange for specific mechanical concepts. St. Paul (2 nd Corinthians III, 14) said: "The love of Christ constraineth us". I dunno what he meant, but the nice thing about the Bible is that you can choose for yourself what it means! It seems helpful to note that the tracks constrain the response of the cars to applied forces (more or less!). It's useful and human to employ the word in a more general sense, and it probably means roughly the same thing to most people. And if not, who cares? "What's in a name? " as someone said! Peter Lissaman, Da Vinci Ventures Expertise is not knowing everything, but knowing what to look for. 1454 Miracerros Loop South, Santa Fe, New Mexico 87505,USA tel:(505)983-7728
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