Physics Question: Are Eyeglasses Mechanical?
- Jeff Stallard
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That link says, "Device that amplifies or replaces human or animal effort to accomplish a physical task." A lens amplifies human effort to accomplish the physical act of seeing. Bada-boom bada-bing!!GaryKelly wrote:http://www.britannica.com/ebc/article?t ... achine&ct=
which I submit is a more appropriate definition of 'machine' than the one found on the likes of hyperdictionary.com
"Reality is the computer hardware, and religions are the operating systems: abstractions that allow us to interact with, and draw meaning from, a reality that would otherwise be incomprehensible."
- GaryKelly
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Where does the "fairly independently" come from? A lever is a machine, so is a pulley; there's nothing independent about them, they need something (usually *someone*) to operate them in order to fulfil the requirement of work.Jeff Stallard wrote:However, the difference between a machine and a tool is that a machine must operate fairly independently.
And not to get nitpicky, you'll note that light doesn't appear in the Encyclopaedia Britannica definition. Probably because the necessary components of "force and motion" don't apply to light. Your argument in respect of 'vector' is specious, since light has no mass.
"It might be a bit better to tune to one of my fiddle's open strings, like A, rather than asking me for an F#." - Martin Milner
- GaryKelly
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At least we quoted our sources, you liberal pinko! Oh wait, sorry JB, it's Amar who's the pinko 'round herejbarter wrote:Science confuses me. I think I'll have a nice lie down in a darkened political thread.
"It might be a bit better to tune to one of my fiddle's open strings, like A, rather than asking me for an F#." - Martin Milner
- jbarter
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You woke me up to tell me that?GaryKelly wrote:At least we quoted our sources, you liberal pinko! Oh wait, sorry JB, it's Amar who's the pinko 'round herejbarter wrote:Science confuses me. I think I'll have a nice lie down in a darkened political thread.
May the joy of music be ever thine.
(BTW, my name is John)
(BTW, my name is John)
- Jeff Stallard
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I was going by another definition I found on the Web that was differentiating between machines and tools. I suppose it's moot in this case, so I'll just drop the "fairly independent" idea altogether.GaryKelly wrote:Where does the "fairly independently" come from? A lever is a machine, so is a pulley; there's nothing independent about them, they need something (usually *someone*) to operate them in order to fulfil the requirement of work.
Yes, and that disturbs me.And not to get nitpicky, you'll note that light doesn't appear in the Encyclopaedia Britannica definition.
A vector quantity defines velocity and direction, not mass. True, mass (or inertia rather) factors when calculating vector changes, but that's not the point. The point is that vector forces are very Neutonian, and vectors are highly relevent when discussing light.Your argument in respect of 'vector' is specious, since light has no mass.
"Reality is the computer hardware, and religions are the operating systems: abstractions that allow us to interact with, and draw meaning from, a reality that would otherwise be incomprehensible."
- jbarter
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I think I'll take up the pipes. It'll be easier to understand.Jeff Stallard wrote:A vector quantity defines velocity and direction, not mass. True, mass (or inertia rather) factors when calculating vector changes, but that's not the point. The point is that vector forces are very Neutonian, and vectors are highly relevent when discussing light.
May the joy of music be ever thine.
(BTW, my name is John)
(BTW, my name is John)
- GaryKelly
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But light is not Newtonian, it's relativistic. If you're going to insist that changes in vector count in the definition of 'machine', then you're saying a mirror is a machine, or any polished surface, or indeed a puddle of water, all of which modify a beam of light's vector.Jeff Stallard wrote:A vector quantity defines velocity and direction, not mass. True, mass (or inertia rather) factors when calculating vector changes, but that's not the point. The point is that vector forces are very Neutonian, and vectors are highly relevent when discussing light.
Heh. I woke up JB!!
"It might be a bit better to tune to one of my fiddle's open strings, like A, rather than asking me for an F#." - Martin Milner
- Tyler
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Good night, of all the topics argued over here, this has got to be the silliest!
oh, by the way...a lever only becomes a machine when it is or has a pivot point or axis to accomplish work. But this opens up the argument of "which came first, the lever or the crowbar?"
oh, by the way...a lever only becomes a machine when it is or has a pivot point or axis to accomplish work. But this opens up the argument of "which came first, the lever or the crowbar?"
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- amar
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yeah, but a lense just sits there and lets things happen. not actively doing anything at all. i mean, is the newspaper on my table add: a machine because it reflects the light from the sun to my eyes?Jeff Stallard wrote:A lens DOES do something. It alters the vector of light energy. It doesn't have to have cogs, chains, and bearings to be a machine. Anything that modifies energy to assist in the performance of tasks is a machine.
Last edited by amar on Tue Jul 19, 2005 9:15 am, edited 1 time in total.
- amar
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but only if the crowbar is made to work, by a person, the person is the machine, the crowbar is just a piece of metal.GaryKelly wrote:I refer you to my previous answer, and expand upon it by suggestion that a lens doesn't modify energy. Even if the lens were completely lossless, then energy in=energy out, and therefore no modification has occured at all.
Amar, a crowbar has no moving parts, but since it operates on the principle of a lever, it can be classified as a machine (since it performs work).
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interesting thought!amar wrote:yeah, but a lense just sits there and lets things happen. not actively doing anything at all. i mean, is the newspaper on my table because it reflects the light from the sun to my eyes?Jeff Stallard wrote:A lens DOES do something. It alters the vector of light energy. It doesn't have to have cogs, chains, and bearings to be a machine. Anything that modifies energy to assist in the performance of tasks is a machine.
So, a stinky guy walks into a bar and by his very presence modifies the air in the room.....
“First lesson: money is not wealth; Second lesson: experiences are more valuable than possessions; Third lesson: by the time you arrive at your goal it’s never what you imagined it would be so learn to enjoy the process” - unknown
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Jeff Stallard wrote:That link says, "Device that amplifies or replaces human or animal effort to accomplish a physical task." A lens amplifies human effort to accomplish the physical act of seeing. Bada-boom bada-bing!!GaryKelly wrote:http://www.britannica.com/ebc/article?t ... achine&ct=
which I submit is a more appropriate definition of 'machine' than the one found on the likes of hyperdictionary.com
but it also says: A machine may be further defined as a device consisting of two or more parts that transmit or modify force and motion in order to do work.