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Law of Conservation of Energy
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how is the law of conservation of energy proved when u have similar Total Energies (kinetic energy + gravtitational potential energy) and why are they similar? T_T i hope i'm making sense.. =/ |
floopy!|
Re: Law of Conservation of Energy
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by SuicidopoliS
on 2006-11-16 06:37:18
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??? If you're talking about conservation of energy in the gravitational field of, let's say, the earth... well, the mathematical expression would be: E_tot = E_kin + E_pot = (1/2)m*v^2 + m*g*h m = mass of the considered object, v = it's speed, g = gravitational acceleration and h = height of the object ( 0 = the ground, not the center of the earth, mind you ). The conservation can be prooved by calculating the work done over the same distance ( say from positing x1 tot position x2 ), in 2 different ways: once explicitly, by integrating the force and stuff ( W = F*x, so that's for the kinetic energy part ), and once using the primitive of the force, by definition the potential energy. Combining the results of those 2 integrals will show you that indeed the total energy hasn't changed. I hear you coming... "But say i remain on the earth's surface, so h remains 0, so i don't have any potential energy, and say i start to run... this gives me speed, so my kinetic energy goes up, so i'm violating the law of conservation of energy?!?" Nope, you're not, because you eat food, which you transform into energy ( and some other things... ) in your digestive system! And i don't really get the part "similar total energies"? The one and only Total Energy there is, is the sum of the kinetic and the potential energies! And those have the same dimensions, which is logical, since ohterwise you wouldn't be able to sum them... but they describe different things. .oO° Life's THE CURE, the rest are details! °Oo. |
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Re: Law of Conservation of Energy
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| ooh okay XD thanks! and thanks for typing that all up O_O wow! |