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Newton 1st same as energy being conserved

  1. Apr 4, 2003 #1

    newton the 1st states:
    when no force acts upon one object its speed is constant.
    this means that at that time (F1,V1)=(0,const).now if this speed drops down to zero the force will rize to some nonzero value and then (F2,V2)=(const,0).the force-speed domain is two-dimensional tush it's a plane.in that plane according to newton 1st there are two events (F1,V1) and (F2,V2) which represent two points on the same plane.two points only define striath line only and the line's equation is:
    this equation is the math form of the newton 1st(honestly).if you implement the values of the events above you'll get:
    F/[da]F=-(V-V1)V1_________________if x/V=x1/V1=t then
    F/[da]F=-(x-x1)/x1________________x1=x2+[da]x and x2=0 => x1=[da]x =>
    (F/[da]F)+(x/[da]x)=1_____________F=F1+[da]F and x=x1+[da]x =>
    F1[da]x+x1[da]F+[da]F[da]x=0______adding F1x1 lefth and right



    P.S.:i wonder why [da] doesn't draw delta!!
  2. jcsd
  3. Apr 4, 2003 #2
    Conservation of Energy

    Question: Do you believe the Universe is a "closed system" and, if so, why are physicists fond of Entropy when energy can NOT be removed from the system? And, while there seems to be a great deal of chaos in the Universe, natural forces tend toward ORDER, ie, spin and gravity causes accretion of "matter" (which is, as we know, actually energy), just as natural ingrediants give rise to life.

    I believe that a similar process is going on in the realm of consciousness, but that's another "matter".....
  4. Apr 4, 2003 #3
    Re: Conservation of Energy

    increases of entropy is more a statement that:

    there are many trajectories the parts of a china bup can take once it smashes on the ground.

    there is only one tranjectory that will put all the peices together again - it's unlikely to happen.

    this has no real bearing on the energy.

    Entropy is not well defined for out of equilibrium systems, so Universal energy might not be a quantity worth considering.

    Also, ordered life on the earth only arose in tandem with the creation of a great deal of disorder in and around the sun.
  5. Apr 7, 2003 #4
    Re: Conservation of Energy

    i can take any system and label it S1.the complementary set which is the universe minus S1 is S2.if S1 is open i.e. exchanging energy it will do it with S2.unifying S1 and S2 gives the universe and it is closed system cause the sum of the energy from S1 and S2 regardles of their changes is constant.
  6. Apr 9, 2003 #5


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    Staff: Mentor

    Hmm... They didn't address your conclusion, dock. Your conclusion is correct. They are the same concept.
  7. Apr 9, 2003 #6
    I must admit that i see your conclusion to be right, but i don't understand how you got it !
    That is true, but that is not the first law of Newton.
    It is true that when no force affects on the body, the speed will stay constant, but it is also possible that a force affects a body, and still the speed is constant (like a body in circular motion).
    Therefore the fact that "No (resultant) force means no change in speed" is not really usefull in physics.
    A more general case (which is the first law of Newton) is that when no (resultant) force is applied, the velocity of the body stay constant.
    Also note that this statement works in both sides (unlike your original statment), so you can also say "when the velocity of the body is constant, no (resultant) force is applied on it", while you cannot say "when the speed of the body is constant, no (resultant) force is being applied".
    Anyway ...
    Who said that the force will be constant ?

    Otherwise, the original idea seems right.
  8. Apr 9, 2003 #7
    at last i found person who shares my opinion about something.

    russ_watters i'll add you in my buddy list because of this!!
  9. Apr 9, 2003 #8
    Re: Re: Newton 1st same as energy being conserved

    Satii you go in my buddy list too.
  10. Apr 9, 2003 #9
    Could someone offer an example...

    of anything at all that has been "set in motion" that will NOT as SOME POINT be "acted upon" by an "outside force."

    Even Voyager might hit something SOME "day" ...or be pulled in by SOME "thing"...etc.

    Newton may have been 100% right...but that doesn't preclude the fact (?) that "cah-cah occurs"!

    I await an example.
  11. Apr 10, 2003 #10
    Since in our world there is no place which is totally empty, and which has no other objects round it (to the distance of infinity), every object is affected by gravitational force, therefore you cannot find any object with no force acting on it AT ALL !
    But, because the newtonian laws were able to explain lot of motion problems, they are considered right (because they also are logical).
    But of course Einstein's Relativity had come to override Newtonian laws anyways !

    EDIT :
    This does not go against Newtonian laws :smile:

    BTW dock, my nick is STAii and not SATii
    Last edited: Apr 10, 2003
  12. Apr 10, 2003 #11

    My point was NOT that it disproved Newton's law.

    I was making a point -- in opposition to current views about the Universe forever expanding -- that "cah-cah occurs".

    I believe that the "cah-cah" that will "occur" for the Universe will be that at some point the "Dark Energy" might undergo a "phase transition" and become "Dark Matter"...causing the Universe to ultimatelly collapse.

    If that is the case, then I couldn't call it "cah-cah" because this would mean that the Universe might collapse to a singularity, which would burst into the NExt "Big Bang" again.

    Expanding into a frigid eternity is not a good "story line" for the Universe. I like it better when the Universe reincarnates over time.
  13. Apr 10, 2003 #12


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    Staff: Mentor

    Re: STAii...

    According to the theories of gravity, there is gravitational attraction between all particles anywhere. Add to that Heisenberg uncertainty and there is NEVER a case when a particle is acted upon by no outside forces whatsoever.

    BUT, that does NOT mean the universe can't expand forever. Two possible cases: If the deceleration of the universe is small and decreasing exponentially and asymtopically toward zero, it will never stop decelerating, but never reach zero. That would happen if the universe were exactly at the "critical mass" for expansion/collapse. Under that critical mass and the expansion would still decelerate asymtopically (sp?) but it will approach some constant expansion rate.
    How exactly is that going to happen? It won't happen simply because you want it to.
    Physics doesn't care about storylines. I'd like it better if it rained money. That doesn't make it happen.
  14. Apr 10, 2003 #13
    Russ Watters...

    I do not believe "phase transitions" are unheard of in physics.

    Are they not somethings caused by changes in temperatures?

    If my tenuous understanding of current theories is correct, "Dark Energy" may be exerting its "outward" force due to the "bubbling up" of energy and elementary particles out of the "vaccuum'"

    This causes cosmologists to conjecture that, because the Universe is EXPANDING at an ACCELLERATING rate, that eventually the Universe will we so "thin" of matter that is "outruns" gravity.

    My conjecture that, perhaps at a certain temperature (or something else) this "Dark Energy" will begin to "freeze down" into matter (maybe even "Dark Matter") which EXERTS GRAVITY.

    And, since "Dark Energy" is throught to comprise approximately 2/3rd of the Universe, such a shift would cause a rather pronounced -- and ongoing - CONTRACTION.

    I believe a similar phase transition occurred a few "moments' after the (last) "Big Bang"...that matter (atoms) "froze out" of the energy...and photons of light were able to travels across the newly formed "space".

    As to "story line" you may soon discover that I put many things in quotes that are either figurative, or not necessarily proven, or recently coined, etc.

    Nonetheless, I am "guilty" of liking the "story line" that the Universe is a living, conscious Entity that enjoys infinite incarnations via the process described above.

    And even certain COSMOLOGISTS don't like the "story line" that has the Universe expanding into a frigid and sparce eternity.
    Last edited: Apr 10, 2003
  15. Apr 11, 2003 #14


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    Staff: Mentor

    Re: Russ Watters...

    You are putting the words "phase transition" in quotes for a reason, aren't you? What you are suggesting is not the same as a phase transition.

    I never said I liked it either. I find it vaguely unsettling. Many people find it depressing. But that doesn't mean I'll try to make up a different theory if the evidence doesn't lend itself to a new theory.
  16. Apr 21, 2003 #15
    Russ Watters...

    A phase transition is a change in a feature that characterizes a system. Examples of phase transitions are changes from solid to liquid, liquid to gas, and the reverse changes. Other examples include the transition from a paramagnet to a ferromagnet, and the transition from a normally conducting metal to a superconductor.

    Phase transitions can occur by altering such variables as temperature temperature and pressure.

    Since "Dark Energy" is said to be expanding the Universe at an accellerated pace so that the Universe will eventually become cooler and less dense, then, theoretically, the stage could be set for such a phase transition to occur wherein the accumulated "Dark Energy" shifts "down" to "Dark Matter" with its attendant gravitational pull inward and, voila, a COLLAPSING UNIVERSE!

    When one reminds oneself that the cosmologist speculate that the "Dark Energy" is caused by the ubiquitous accumulation of energy and elementary particles "coming out of" the vacuum, one might see how Universe might get "crowded" with the stuff, to the extent that something ELSE happens.

    And if fresh water becomes catostrophically scarce, it may indeed -- some day -- rain money! So, take heart.
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