Talk:Conservation of energy
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Hi, to me this formula is much better do discribe the first law:
- <math>\frac{d}{dt}\int^{}_{V_{kv}} \rho \left( u + \frac {w^2}{2}+ gz \right) dV = \sum_{k} \left[ \dot{m}\left( h + \frac {w^2}{2}+ gz \right)\right]_k + \dot{Q} + \dot{W_t} - p \frac {dV_{kv}}{dt}<math>
Smily1306
This doesn't make any sense.
- The classical form of the energy conservation law (and in fact the notion of energy in the first place) is directly related (through the corresponding equation of motion) to the force- concept describing the interaction of particles. The latter can be shown to be necessarily instantaneous (i.e. Newtonian) as otherwise one would not be able to define a force objectively, i.e. independent of the state of motion of the observer. One can therefore say that the law of energy conservation does, by definition, only strictly hold for this case of a static interaction of particles, but is not more than an arbitrary ad hoc concept if applied to other situations, in particular those involving light: two light waves can be made to extinguish each other completely if superposed with the correct phase, which proves that a form of energy conservation does not apply here.
--- Roadrunner
energy equivalence / conservation of energy?
I'm not a physicist or an engineer, but is conservation of energy really considered a special form of mass/energy equivalence? I would have expected it to be the other way around -- conservation of energy seems to apply in far more situations than mass/energy equivalence. Could somebody clarify this for me? --Fastfission 05:11, 6 Apr 2005 (UTC)
- I see your confusion. That section was worded ambiguously. Check the way it is written now, and let me know if the matter is still unclear. — Cortonin | Talk 14:34, 6 Apr 2005 (UTC)
nguyenvantien