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| T3sl4co1l:
In a colloquial sense, it's things in motion; having energy. But that's different from an amount of energy in joules or whatever. Have you dome intro physics, mechanics? Definition of position/velocity/acceleration, Newton's laws, etc.? That's a good place to start. Tim |
| TimFox:
--- Quote from: typoknig on April 08, 2022, 03:42:04 am --- --- Quote from: TimFox on April 07, 2022, 03:40:11 pm ---No, "current" is not a measure of energy. In normal electrical units, the "watt-second" is energy, usually referred to in physics as the "Joule". --- End quote --- An excerpt from Wikipedia's Electrical Energy article: "Electrical energy is energy derived as a result of movement of electrically charged particles." An excerpt from Wikipedia's Electric Current article: "An electric current is a stream of charged particles, such as electrons or ions, moving through an electrical conductor or space." By those definitions and, I would argue, any common definition of "energy", current must be considered energy. Sorry if I'm being thick Tim (I really want to understand this, that is why I keep asking questions about things that don't seem to jive), but what is it about the definition of energy that makes it not apply to the definition of current, based on your understanding? --- End quote --- "Energy" is a defined term in physics, and I follow that definition. As an example, the velocity of an automobile is not its energy. The kinetic energy of the automobile is E = (1/2)mv2, which depends on both the mass m and the velocity v. Increasing the velocity increases the energy, but is not the energy itself. This is careful, not pedantic, usage of the word "energy". In popular usage, breakfast cereal gives a child "energy", but that is not scientific usage. |
| T3sl4co1l:
And to be clear -- I don't mean to patronize or belittle, I honestly don't know your education level so don't know where to start. Energy is an abstract concept, it's not trivial to understand; it takes time and care to develop. It's a sizable part of the relevant HS/college level classes, for good reason! And well worth reading up on, if you haven't worked with it before (or in a while; a refresher is always welcome, too!). Not sure what the best resources are these days; there's always Wikipedia and Hyperphysics, though they have the downside of tending to present information from within the domain itself, so aren't always that approachable from the outside. Tim |
| typoknig:
--- Quote from: TimFox on April 08, 2022, 12:30:42 pm --- --- Quote from: typoknig on April 08, 2022, 03:42:04 am --- --- Quote from: TimFox on April 07, 2022, 03:40:11 pm ---No, "current" is not a measure of energy. In normal electrical units, the "watt-second" is energy, usually referred to in physics as the "Joule". --- End quote --- An excerpt from Wikipedia's Electrical Energy article: "Electrical energy is energy derived as a result of movement of electrically charged particles." An excerpt from Wikipedia's Electric Current article: "An electric current is a stream of charged particles, such as electrons or ions, moving through an electrical conductor or space." By those definitions and, I would argue, any common definition of "energy", current must be considered energy. Sorry if I'm being thick Tim (I really want to understand this, that is why I keep asking questions about things that don't seem to jive), but what is it about the definition of energy that makes it not apply to the definition of current, based on your understanding? --- End quote --- "Energy" is a defined term in physics, and I follow that definition. As an example, the velocity of an automobile is not its energy. The kinetic energy of the automobile is E = (1/2)mv2, which depends on both the mass m and the velocity v. Increasing the velocity increases the energy, but is not the energy itself. This is careful, not pedantic, usage of the word "energy". In popular usage, breakfast cereal gives a child "energy", but that is not scientific usage. --- End quote --- Can you provide a reference to the physics definition? I'm assuming you are saying it doesn't match the definition provided in the Wikipedia articles I referenced? I dusted off my physics book (Cutnell & Johnson Physics, 6th Edition, (C) 2004) and its definition can be seen in the attached picture. I guess I could maybe see how someone could/would not consider current "energy" by this definition since it is the field causing the particles to move, but I think it is a stretch. Once the electrons are moving, they have had "some" energy imparted to them, so even if the field is what caused them to move in the first place, if the field is removed there will be some span of time (short as it may be) that the electrons will still be flowing, correct? |
| IanB:
--- Quote from: typoknig on April 08, 2022, 06:07:44 pm ---Can you provide a reference to the physics definition? I'm assuming you are saying it doesn't match the definition provided in the Wikipedia articles I referenced? --- End quote --- The definition of energy is fundamental, and is addressed in any introductory physics or thermodynamics text. This is not an area where Wikipedia should be a primary reference (all Wikipedia articles have to refer to primary sources for any facts they give, so you might consider following the references to primary sources given in Wiki articles). It is, incidentally, the case that nobody really knows what energy "is". It is simply a quantity that has been observed through countless experiments to be conserved, and which obeys various rules that also have been determined by experiment. There is no intuitive way to say that the thermal energy in a hot cup of coffee is the same "stuff" as the chemical energy stored in a battery, but experimentally it is proven to be the case. |
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