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*To*: sagitta_elegans@yahoo.com*Subject*: Re:*From*: "James R. Cunningham" <jrccea@bellsouth.net>*Date*: Mon, 10 May 1999 12:27:18 -0700*Cc*: dinosaur@usc.edu*References*: <19990510105635.19481.rocketmail@web110.yahoomail.com>*Reply-to*: jrccea@bellsouth.net*Sender*: owner-dinosaur@usc.edu

Bill Adlam wrote: > Work is the amount of energy changed from one form to another (i.e. > expended). It doesn't have a direction. When an object moves, work > is equal to force times distance. > > Bill Almost, but not quite. When a force is applied to a solid object constrained so that it can move only in a plane oriented perpendicular to the force, then the force exerts no work on the object. In other words, a 50 pound vertical force acting on an object which moves 10 feet horizontally across a frictionless plane, results in zero work rather than 50 foot-pounds of work. Needless to say, this description implies that the horizontal motion is not a consequence of the vertical force. Of course, work can be described in more than one way. For example, one of the ways 'flow work' can be done on a fluid system is when the pressure forces on the boundaries move, for example in a tapered cylinder when p1A1 and p2A2 at the end sections move through delta S1 and delta S2 respectively. We could go on with different scenarios at length, but again I think we are moving away from dinosaurs. Jim

**References**:**[no subject]***From:*Bill Adlam <sagitta_elegans@yahoo.com>

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