How many conservation laws ?

  1. Hi
    How many conservation laws are there ?
    1. Conservation of energy
    2. " " momentum
    3. " mass
    4. " charge
    ????


    TIA
     
  2. jcsd
  3. energy
    momentum
    angular momentum
    charge
    gravity
    + others I can't think of right now

    mass conservation isn't really true
     
  4. I like Serena

    I like Serena 6,194
    Homework Helper

    color charge
    weak isospin
    probability density
    CPT symmetry (combining charge, parity and time conjugation)
    Lorentz symmetry

    (ripped from http://en.wikipedia.org/wiki/Conservation_law)
     
  5. Drakkith

    Staff: Mentor

    Yeah, It all depends on what you mean by "mass". Converting electrons-positrons to gamma rays removes the "mass" and turns it into energy or momentum or whatever.
     
  6. Vanadium 50

    Vanadium 50 18,160
    Staff Emeritus
    Science Advisor
    Education Advisor

    I don't know what "conservation of gravity" even means. As for weak isospin, it is certainly not conserved, although it's third component is.

    There is no answer to this question. What is conserved and what is not depends on the state you are looking at: an object in a central force orbit always has angular momentum conserved, but in a 1/r potential, it also has another quantity conserved: the Runge-Lenz vector.

    Additionally, if x and y are conserved, x + ay is conserved as well, for all values of a. So if there are two, there are an infinite number.
     
  7. Drakkith

    Staff: Mentor

    I think the OP was simply asking about the "Conservation Laws".

    From wikipedia, it lists a few things seperated into "exact laws" and "approximate laws".
     
  8. Would it then be correct to say that a conservation of matter doesn't exist, but a conservation of mass does, seeing as energy does possess mass?
     
  9. Drakkith

    Staff: Mentor

    As wikipedia put it, I'd call it Conservation of mass-energy.
     
  10. The concept of mass–energy equivalence connects the concepts of conservation of mass and conservation of energy, which continue to hold separately. The theory of relativity allows particles which have rest mass to be converted to other forms of mass which require motion, such as kinetic energy, heat, or light.From WkiPedia.
     
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