Not you, the guy who knows less about physics than I do. (Thats pretty damn BAD.)

Wait wait wait. F=ma doesn't exist? Did you pass high school physics? If you did, I would sorely recommend you repeat that class...probably more than once. It's one of Newton's Laws and it has stood up to timeless tests and each one it has been proven flawless. I push on a mass, I exert a force on it which causes it to accelerate. If I accelerate in a direction, some form of force is applied causing me to accelerate.

Who are you talking about?

Your mom.

She isn't that bright.

Of course my mom isn't bright. She isn't bioluminescent.

Dude, that was lame.

Just.. go home. You lose. Get off the internet, because I have alpha nerded you.

Hey, I do maths for a living - now *that's* ubergeekdom.

Rob, stop crapping on these intelligent discussions of threads. Please. It's not funny, and it's getting old.

What you need to understand is that mass as we understand it does not truly exist. Mass is not an inherent physical property resulting from the makeup of an object, but rather the effect energy has upon the gravitational field. "Mass" is not much different from electric charge. How would a different mass "appear" to an observer? You're pulling all of this out of your ***.

Wow. all i can say is wow. i had to stop my lurking for months jsut to have a go at this one. So, first, while you seem to accept that Newtonia Physics is real, you say it only applies in deep space? Bull crap. All you ahve to do to apply newtonian forces to the earth is to factor in all forces acting on an object. its called vectors. i leaned about them in junior high. But that's not even the worst. now, you proceed to say that F=MA, one of the fundamental parts of NEWTONIAN physics, doesn't exist? what? What, pray tell, causes acceleration, then? What effect does a force have on an object, then? The froces that you mention, the downward potential of the book and upward force of the table, do exist, because, if they didn't, then yes, the book would indeed fall through the table, because if no force acts upward, the book goes down! *gasp, shock* yes, folks! if a force acts in a downward direction, and nothing acts in an upward direction, the object the force is acting on moves downward! while you're all caught up in your fancy 'elastic tenion' and so forth, which you probably overheard from a physics teacher that you don't have because he teaches the advanced kids, what you fail to realize is that while, yes, these do exist, THEY CREATE THE UPWARD FORCE! In being what keeps the book in its place, they are creating the force which counter-balances mg!

Oh, adn the book would not break through the table, short of someone firing sand blaster at it, unless it was an oragmi table or something. becuase, the thing is, with msot tables, the forces holding it together are far strong then the force the book has. unless you overcome this, adn create enough force to overcome the modulus of elasticity (now that's a big technical term. Do you know what it means? i bet you probably don't, though i'm sure JB could tell you in a second. no using google, now!) of the table, no effect is sustained by the table. you must use a force which has a permenant effect, one greater then the modulus of elasticity, ikn most cases, in order to exact eventual results. granted, only extreamly slighty excessive force may take an very long time to act, it still has a constant effect, even if it too small to see. a pile of snow doesn't jsut suddenly think "i've had enough!" and topple over to create an avalanch. some excessive force must trigger it. the force needed may be tiny, perhaps no mroe then the vibration of air molecules from someone yelling, or one snowflake too many, but the excessive force is still there. a 30g book on a stone table will never break through it, because it does not provide the necessary excessive force to create any sort of permanant effect.

More later, i need to read up on the rest of your posts

[QUOTE=Dj Yoshi]Rob, stop crapping on these intelligent discussions of threads. Please. It's not funny, and it's getting old.[/QUOTE]

He only came into the convo to talk about CaptBevvil, so i hardly consider him to be messing up 'intellgent conversation'. were he to insult JB or something, then sure. but right now, he's doing nothing

You had me there for a few seconds until I remembered that the modulus of elasticity is the same as Young's Modulus...you find that so often in physics, many names for the same blasted thing....You've explained the whole F=MA thing nicely and hopefully put to bed a few questions anyone may have had.

as for Youngs Modulus, or the modulus of elasticity, whatever you want to call it is used to model the behaviour of materials when under load, ie when a force is being exerted on a wire for example in pulling it.

It can be used to predict the amount the wire will extend under a given load and also can be used to predict at which point concret, for example, will buckle under compression.

Its meant to model Linear materials (metal, glass, carbon) only, ie not rubber which has the funny property of its atoms being able to slide over one another before conforming to Young's Laws (for only a short time before it breaks)...thats why you can stretch rubber a long way but after a certain point it won't return back to its normal shape.

last time I did any of this was nearly 4-5 years ago...its good to remember the basics every now and again.



Your logic is flawed...what lasts longer? a book or a table?...I don't see many 400 year old books that can be used everyday, where as I know for a fact there are tables that old still in everyday use.

Thats not to say that your argument was right in the first place, but still, a table will outlive a book.

I'm sad because even if you can get light to stand still, you still can't see it.

Which is why house settlement would occur much faster.



Fine, replace each instance of the word "book" with "solid block of steel." The point is, the downward pressure of the atmosphere (or what we generally accept as calling "gravity") causes strain over the table area that it covers. This is a constantly applied strain which causes the tension to climb the elasticity curve. Eventually, it'll hit the breaking point and the book/block/whatever will fall through. This may take 100+ years to do it, but the point is that there is not that so called claimed "equilibrium" in between the two objects.



Yes, because if you recall the work-energy theorim, you have W(sub f) = W(sub i) - W(sub c), where W(sub c) is the work of the non-conservitive force, ie. friction. "Once in motion, always in motion" is only true in the absence of friction (and/or gravity as the case may be). [read more below]

Again, F=ma is fine for mathematical purposes. Especially in the use of calculating vectors.



There is no mysterious "force." It's mechanics. A lot of the confusion is caused due to the way that "kinetic energy" is explained in physics (see above quote & responds). On earth, you push a ball and it accelerates while you're pushing it, but then imediately begins to decelerate due to friction after your hands release it. In deep space, if you push a ball, it accelerates while you are pushing it and then maintains a constant velocity (because there is no friction slowing it down). The only way to maintain an "observed" constant velocity on earth is to achieve an equilibrium of acceleration where you are just barely overcomming the resistance caused by friction at/for that speed.

[proof]
At each speed in a car, in order to maintain constant velocity, you must maintain a constant acceleration (translated as a constant burning of fuel).
[/proof]

So what we preceive or "observe" is a constant velocity on earth, is actually constant acceleration against the constant resistance caused by (or summed up as) friction that is applied to the object being accelerated.

Any more questions, comments, ideas, etc?

Downward pressure of the atmosphere is NOT gravity, and never will be.

How can you claim such knowledge about complex systems, and not understand this simple concept? You are trying to compare apples and oranges, and you'll forever come up short.

Gravity is a fundamental force that is found EVERYWHERE in the universe, not in just planets with atmospheres. In fact, w/o gravity, we have no atmosphere. Even you exert some form of gravity.

Anyway, constant velocity can be achieved on this planet. Newton's Second Law is really F[net] = ma which means F[0]+F[1]+F[2]...F[n] = ma. If all the forces acting on an object cancel each other out, then the net force is 0 and thus acceleration is 0. Me keeping the accelerator on provides the force counteracting drag, friction, etc. Trust me, I've been able to keep the needle pointing exactly at 80 MPH for long periods of time.

Aye sir. The JG speaketh more truth.

:eek:ARGH!!!!!!:eek:

Its still bloody flawed, not withstanding the fact that your whole idea of pressure=gravity is wrong and which has already been covered by martyn & JG.

Why in space do things fall to earth?? theres no atmosphere out there...have you ever heard of the Standard Model? if you have you should be able to tell me what gives something mass and do not say the number of electrons/protons/neutrons. Imagine you are in space and at a point where no gravity exists, you would still have mass, why?

let me also point out my background in this area, I'm a physics postgraduate who will be starting his Master's in the subject come september at one of the top 10 physics departments in the UK. I'm not saying i'm perfect, far from it, I make stupid mistakes all the time in exams and I consider myself an idiot compared to my lecturers but this I know....

Newton's laws are correct, do not argue with this fact, you may only point out that they are not correct at relativisic speeds and atomic sizes.

If you account for all variables as JG pointed out they will give you a correct answer to however many decimal places you entered it in, in the first place and it will be right. The laws are simplified for everyday use, do you want to be a rocket scientist? go learn newton's laws.

Getting back to the statement in hand, say I stand on an ideal metal grider (the perfect metal, no imperfections, pure metal) thats spans across a valley, I also live forever and my sole purpose in life is to stand on this grider through sun, wind, snow, rain everyday of every year of my life till the end of my existence.

Not only would this a very boring existence it would ultimately end when the grider gives way to my weight. Now why does it give way? it has nothing to do with physics other than the direction I fall, it has far far much more to do with chemisty (which is still physics but I'll let that one point drop...for now).

If the girder can withstand my weight without buckling or going near its tensile strength it could hold my weight forever in a perfect vaccum. I say vaccum, in the sense that the grider and I (who have become good friends after the few millenia we have spent together) are immume to all outside forces bar gravity.

This is an important factor, what causes buildings and bridges to collaspe over time? corrision, or more specifially the degradation of the order of the crystalline structure of the metal/material, through either oxidisation, fracturing or other similar effects.

the grider will only give way to me if exposed to the elements, oxygen molecules will slowly corrode the surface, water molecules will then be able to enter into the lattice and join with the metal atoms. Then when the sun shines they evapourate and take with them some of atoms, this process will go on and on and is slow in its progress.

The wind will also effect it, buffeting it and me causing my weight to change as I am moved causing the molecules within the grider to move up and down increasing the size of the atomic cracks caused by the water to widen...just like in rocks.

Sun hot = expand, winter cold = contract....

Hopefully by now you get the idea...

Then just after the grider and I have married and begun family planning, it will break, not because it couldn't bear another second with me, but because outside forces weekened it. (I really need to get out more)

It is a hard concept to understand I agree, we are all used to things breaking over time, however in an ideal world nothing would break unless we wanted it to.

No matter how long I stand on the grider in a vaccum the effect of my weight won't change. The molecules in the lattice will be pulled apart yes, but their bonds broken, nope. They will be pulled apart a certain distance and then not move any further unless I apply more force to do so.

Also not all molecules will be pull apart, some will be pushed together, you then come into the realm of the coulomb potential, this is a force that rises expotenially the closer you get to the nucleus of the atom and it repels motion towards it, it only however acts at very short distances.

I've gone over this argument many times in my head thinking of a flaw, I can't think of one, if anyone has any problems with what i've said please post...it was kinda suprise myself to realise that if you cancel out all other forces the grider would never break...

Nope, you've pretty much covered it. I knew all that, but would never have been able to put it so succintly.

No. no no no no no no no no no no no *gasp* NO. How can you possibly begin to think you understand inertia if you mess it up this badly? the actual statement is "An object in motion will stay in motion at a constant velocity until acted upon by an external force". Friction is an external force, and so inertia in the classical definition is still completely true! F=MA still works! Granted, in everyhting otehr then deep space with only one source of force, you bdo need to get more complicated, but it still stands. where there is more then one force, the actual equation is EF=MA (E refers to the 'Sum of' symbol, i can't seem to display it on the boards), nad EF is the sum of all forces acting on an object. In the case of the car you mentioned, barring the effect of wind and flies hitting the winshield and such, the actual equation would be

F(motor) + F(friction) = MA
and
F(friction)=Coefficent of Friction*-mg

If traveling at constant velocity, F(Motor) would be the same as -F(friction), Making 0, so that no matter the mass of the car, A=0, and constant velocity. EF=MA is still true.

(sorry, JG, i know you explained this, but i felt his bungling of Inertia required a little more attention)

I must ask, bevvil, why you consider yourself not only more intelligent then JB, who is a college graduate, but more intelligent then every physist who has ever tested Newton's laws?

Firstly:



Hee hee. Should be "theorized their existence with another theorem", no? Theories can't "prove" other theories unless they are... really proven true.

Second... When I read that passage about the girder lasting forever, I laughed. Somehow that struck a chord with my interest in physics/architecture.

Thirdly, a question. In our black hole scenarios, earlier in this thread, what prevents the matter being drawn in from breaking down to a size smaller than that of a single atom? This is pure conjecture (and I'm not really theorizing at all, I'm asking)... does this have anything to do with the fact that the Strong Nuclear Forces are.....stronger than gravity? If not, what prevents this constriction of volume or whatever from proceeding past that point...?

we do assume this, I (or more rightly my girlfriend Jo) left it at just the atomic point as not to confuse anyone...

as far as we currently know the atom's will be ripped apart into their quarks and leptons and possibly even further, we currently can't say if these particles are the final building blocks or not, we are pretty sure but not 100%

A lot of people are looking at Super-strings as the next and (hopefully) final step, but simply put, entering the black hole would split you down to your smallest part and stretch it too (as far as we know) infinity....what a nice thought eh?

as to what comes out the other side, only wild guesses and theories really, nothing at all concrete yet to say the least.

we have however detected x-rays and gamma rays coming out as yoshi pointed out, we assume this is a result of the break up of the atoms, but until we can really study a black hole in depth all this is conjecture and educated guesswork/ mathematical theory.

[edit] Future post, or at least Yoshi's is[/edit]

Gamma Rays and X Rays are emitted, so that's assumed to be the atoms splitting up and the parts getting spit out of the black hole.

Whee, I got something right. I knew reading all those wikis would help someday
:x

Are you aware of how many pounds of downward pressure is applied to the top of your head?

[quote=James Bond]Its still bloody flawed, not withstanding the fact that your whole idea of pressure=gravity is wrong and which has already been covered by martyn & JG.

Why in space do things fall to earth?? theres no atmosphere out there...have you ever heard of the Standard Model? if you have you should be able to tell me what gives something mass and do not say the number of electrons/protons/neutrons. Imagine you are in space and at a point where no gravity exists, you would still have mass, why? [/quote]

Actually, that's incorrect. There is a thin "atmosphere" in our solar system just like there is a thin "atmostphere" around our entire galaxy.

Don't confuse mass m with weight mg. And no, it's not the shere number of electrons/protons/neutrons (that contributes to the total mass) it's that electrons/protons/neutrons have mass. Which is why that anything that exists has mass.

If you were in a true vacuum, there would be no gravity. Hence, you would not be exerting any "force" on the grider.



No, you are forgeting that you are applying constant acceleration (costant fuel consumption) to maintain a "preceived" constant velocity. Also, you are loosing mass (due to fuel consumption).



I never made that claim.

[quote=James Bond]Newton's laws are correct, do not argue with this fact, you may only point out that they are not correct at relativisic speeds and atomic sizes.[/quote]

I never said they were not correct (at least, at the fundamental and conceptual levels). However, a better equation would be F=mv[sub i] where v[sub i] = instantaneous velocity relative to the observer. In other words v would not be the same for a stationary observer as it is for an observer moving in the same or opposite direction. To give an example, the "Force" exerted on a car rear ending a stationary car is greater then that of rear ending another car going in the same direction.

[note: I never use a 3rd part observer in my examples (as Einstein did), I have a rule that states that "the true effects of an event can only be calculated using classical physics from the perspective of an observer that exists in the same inertial frame as the event." This does not mean a stationary 3rd party observer cannot calculate the effects of the event, it only means it has to take the instantaneous velocital (yes, a word I coined) difference into account. The reason for this is that in Einstein's simultatinality(sp?) example, he gives a box car traveling at a constant velocity v (remember, this is actually constant acceleration) and being struct by light at the front and the rear at the same time at the exact moment it passes an outside observer. The example goes on to make clear the that outside observer was the same distance from both lighting strikes. The outside observer observes the lighting striking at the same time, while the observer inside the box car observes the lighting strike in the direction he was travel moments before the one occuring behind him. Einstein claimed that both observations were correct. THIS IS WRONG. The above rule corrects this. The outside observer was the only observer observing the event in the same inertial frame as the lighting. The other observer was inside a box car traveling a constant velocity different from that of the outside observer and thus existing in another inertial frame. He sees the first one first because between the time it takes the light from the lighting to reach his eyes, he has reduceded the distance to the lighting in front of him and increased the distance to the lighting strike behind him while the outside observer was an equal distance to both lighting strikes. The reason they don't see the same thing is because the speed of light isn't instantaneous.]

All of which is the cause of gravity. Re read all our posts about this again.


Ergh. Re read what we all said again. OVERALL you are moving at a constant velocity because the NET FORCE is ZERO. Yes you are providing a force that counteracts all retarding forces (friction, drag, etc). There is nothing perceived about it. You are assuming that just because you're pushing on the accelerator that means you are constantly accelerating. Acceleration is defined as change in velocity per unit time. You cannot be accelerating if your speedometer is reading 80 MPH for given period of time.


You cannot just rewrite the equations like that. F does not and will never equal mv. That's momentum p=mv. In the example you are talking about a system of particles colliding. There's another slew of equations dealing with collisions (elastic, inelastic, etc.)

F=ma

Real scientists work in metric, and yes I am, and IT STILL IS NOT GRAVITY.

Gravity is a force which is a function of mass, and the square of distances between objects. Air pressure is in, the case you are trying to explain, the weight of the column of air atop a surface, weight being a FORCE CAUSED BY GRAVITY.

GRAVITY IS THE WARPING OF SPACE TIME AROUND MASSIVE OBJECTS, AIR PRESSURE IS THE WEIGHT OF AIR.

THEY ARE *COMPLETELY DIFFERENT,* AND THIS IS THE ABSOLUTE LAST TIME I AM EXPLAINING THIS TO YOU.

This could start getting ugly.


Your being pedantic and you know it!

yes there are dust particles, but go look up the meaning of atmosphere in the dictionary...no in fact here is what it says at dictionary.com

1. The gaseous mass or envelope surrounding a celestial body, especially the one surrounding the earth, and retained by the celestial body's gravitational field.
2. The air or climate in a specific place.
3. Abbr. atm Physics. A unit of pressure equal to the air pressure at sea level. It equals the amount of pressure that will support a column of mercury 760 millimeters high at 0 degrees Celsius under standard gravity, or 14.7 pounds per square inch (1.01325 × 105 pascals). See table at measurement.
4. A dominant intellectual or emotional environment or attitude: an atmosphere of distrust among the electorate.
5. The dominant tone or mood of a work of art.
6. An aesthetic quality or effect, especially a distinctive and pleasing one, associated with a particular place: a restaurant with an Old World atmosphere.

space does not have an atomsphere. period!

the area between our planets we call the ISM (Interstella Medium) it is a better class of vacuum than anything we can currently create on Earth and will continue to be so for a while yet.



why should anything have mass? why should an electron have mass? a photon exists, it doesn't have mass, and do not use wave-particle duality to get out of that one!

plus you've also proved in that last statement your level of knowledge of physics because of the stuff you didn't mention...your knowledge is where I was at the age of 14-15. You haven't mentioned anything about quarks, the higgs boson, leptons.

Why is it we can just assume something has mass? and what causes mass to even be effected by a gravitational field?



Again, dictionary.com is my friend.

#
1. Absence of matter.
2. A space empty of matter.
3. A space relatively empty of matter.
4. A space in which the pressure is significantly lower than atmospheric pressure.

# A state of emptiness; a void.
# A state of being sealed off from external or environmental influences; isolation.

You could take the last point and agrue it, but don't even try it. A vacuum in all sense of the word in the scientific community means an absense of matter, gravity is always assumed to be acting.

And as for the girder example move it out into space, imagine it is anchored somehow and I am laying flat in the plane of the solar system and the girder is the only thing stopping me falling. The girder will NEVER break!! not after a million years not after a billion billion billion etc.... years, my example still stands.



I really don't know where your argument is going with this, you are just re-iterating what InsanityDecends said but there is nothing "perceived" about it, you will be doing the same speed if everything balences....how do cruise controls work...

it balances the need to keep the same speed by applying more acceleration through the engine to counteract the forces slowing a car down. As the car burns fuel the motor doesn't have to work so hard...so what...

Newton's laws apply to this perfectly and can model it perfectly, the same set of rules are used to model how much fuel the space shuttle needs to get into orbit, or at what angle, what speed and in which direction a rocket needs to be fired to land on your head.............. :em321: theres some pressure for you.



firstly if you are going to quote the laws, quote them correctly, F=MA not MV, MV is momentum.

and all you have just said there is taken into account when applying the laws, what ever examples you must be doing at school must be simple because Newton knew full well about instantaneous velocities...

I can't be sure about your knowledge of his laws but its definatly not all there...

go read this http://hyperphysics.phy-astr.gsu.edu/hbase/newt.html it's only pretty basic but it should hopefully show you enough.



firstly Newton coined the term instantaneous velocity many years ago, its used a lot now-a-days too...

secondly your saying in that example Einstein view is wrong....any evidense to back it up?? if so your looking at a noble prize.

I'm not sure what you hope to point out by your example but you haven't learnt relativity by the looks of it...because you are saying Einstein is wrong when in fact he is perfectly correct, because your still thinking in the Newtonian world if you believe you must be in the same interial frame as the event to truely measure its effects your 500 years behind the times.

You are correct in thinking you'll see the beam in front before you see the beam behind, but you would have to travelling at near the speed of light to notice a difference and even then, it would not be what you expected if you used Newtonian mechanics.

Let me show you this example...



try and get your head around that.

also as long as you know what you are doing and apply relativity correctly it doesn't matter what frame of reference you are in and whether or not you are moving or standing still...

see muon example

http://hyperphysics.phy-astr.gsu.edu/hbase/relativ/muon.html

I leave for a week's holiday tomorrow and if I come back and find you've posted again saying Newton and Einstein are wrong....well, I'll set my lecturers on you and you don't want them coming after you, especially Prof. Thompson.



[edit] looks like while I was writing that stupidly long reply some others joined in the fun...[/edit]

One thing I just thought of that might drive the point of the equivalence of mass and energy home: An atom is heavier than the sum of the masses of its components. The difference in the mass of an atom and the mass of its components is the result of energy, in the form of potential energy on the electrons, and the nuclear strong force holding the nucleus together, among other things. You obviously don't understand this:

Hadrons (neutrons and protons) and leptons (electrons) having mass isn't why all of matter has mass. It's the net energy contained in that matter. Hadrons are composed of three quarks. Quarks themselves do have mass, resulting from the energy of their wave function, and again the mass of the neutrons and protons is greater; this is from the energy binding the quarks together.

[QUOTE=James Bond]yes there are dust particles, but go look up the meaning of atmosphere in the dictionary...no in fact here is what it says at dictionary.com

space does not have an atomsphere. period!

the area between our planets we call the ISM (Interstella Medium) it is a better class of vacuum than anything we can currently create on Earth and will continue to be so for a while yet.[/quote]

1. The gaseous mass or envelope surrounding a celestial body, especially the one surrounding the earth, and retained by the celestial body's gravitational field.

I throw any type of particles, not just gas particles, into that definition. Solid particles contribute just as much if not more to the pressure of the atmostphere as the gas particles do (if not more so). You can not lean on dictionary.com to be an absolute explination or description of anything.

[quote=James Bond]why should anything have mass? why should an electron have mass? a photon exists, it doesn't have mass, and do not use wave-particle duality to get out of that one![/quote]

I've already answered this one (and in rather simplistic terms, actually).

[quote=James Bond]plus you've also proved in that last statement your level of knowledge of physics because of the stuff you didn't mention...your knowledge is where I was at the age of 14-15. You haven't mentioned anything about quarks, the higgs boson, leptons.[/quote]

I like to keep my explination so that a 13 yr old can understand it. By your level of knowledge that you have demonstrated, I can assume you understand the underlying principles and I do not need to go into unnecessary details that would only serve to confuse the younger members of this forum.

[quote=James Bond]Why is it we can just assume something has mass? and what causes mass to even be effected by a gravitational field?[/quote]

For your first question, in reality, "mass" (quote/unquote) does not exist any more then "length" or "time." They are we consider "Fundamental Constants." It's actually more of a base line for comparison...or starting point, if you will. All three are actually just concepts, nothing more.

As to the second part, hypothetically speaking, since no one really knows what causes gravity (and for it to behave the way it does) what if the "gravitational field" we experience is actually the result of the magnetic field that surrounds stars, planets, etc. and pressure. What if in the creation of these bodies, a thin layer of metalic particles surround the planet and then are trapped in it's magnetic field creating a barrier of sorts for the rest of the atmosphere holding the majority of the atmospheric material inside. The atmospheric material (air and other particles) then bouce off this thin metal layer as they do off of each other building downward pressure. This is, of course hypothetically speaking. But if you look at the planets and moons in our solar system, their "gravitational field" is fairly proportional to their overall (average) atmospheric pressure.

[quote=James Bond]Again, dictionary.com is my friend.

#
1. Absence of matter.
2. A space empty of matter.
3. A space relatively empty of matter.
4. A space in which the pressure is significantly lower than atmospheric pressure.

# A state of emptiness; a void.
# A state of being sealed off from external or environmental influences; isolation.

You could take the last point and agrue it, but don't even try it. A vacuum in all sense of the word in the scientific community means an absense of matter, gravity is always assumed to be acting.

And as for the girder example move it out into space, imagine it is anchored somehow and I am laying flat in the plane of the solar system and the girder is the only thing stopping me falling. The girder will NEVER break!! not after a million years not after a billion billion billion etc.... years, my example still stands.[/quote]

Again, dictionary.com is NOT your friend. See above.

[quote=James Bond]I really don't know where your argument is going with this, you are just re-iterating what InsanityDecends said but there is nothing "perceived" about it, you will be doing the same speed if everything balences....how do cruise controls work...

it balances the need to keep the same speed by applying more acceleration through the engine to counteract the forces slowing a car down. As the car burns fuel the motor doesn't have to work so hard...so what...[/quote]

Okay, now take away everything else and put it in a void. Replace the engine with a rocket and the accelerator controls the amount of fuel that is burned. Now Press down on the accelerator and hold it about half way, as if you were trying to maintain 60 or so MPH. Except in this case, you wouldn't be maintaining velocity, you'd be accelerating.

[quote=James Bond]firstly if you are going to quote the laws, quote them correctly, F=MA not MV, MV is momentum.[/quote]

Re-read my post, I posted:
However, a better equation would be F=mv[sub i] where v[sub i] = instantaneous velocity relative to the observer. In other words v would not be the same for a stationary observer as it is for an observer moving in the same or opposite direction. To give an example, the "Force" exerted on a car rear ending a stationary car is greater then that of rear ending another car going in the same direction.

I didn't misquote them, I created a new one that would better represent F in such a way that it could be used in any instance.

[quote=James Bond]and all you have just said there is taken into account when applying the laws, what ever examples you must be doing at school must be simple because Newton knew full well about instantaneous velocities...[/quote]

No, it's not the same thing. Most the example I recall from my Physics lectures used "instantaneous velocity" to get away from taking acceleration into consideration. It's geared to beginner physics equations where acceleration is added in a later chapter or section.

My reference to instantaneous velocity is different in that it allows you to use the Force formula I posted above to get the "relative force" at any given moment. To give a "math" analogy, it's like what calculus does to those old algebra equations. Such that, instead of only knowing what your initial "force" and final force is, this formula would allow you to calculate the force at any given moment of time (particularily in an acceleration curve where the instaneous "force" would be changing proportionally to the change in velocity).

[quote=James Bond]I can't be sure about your knowledge of his laws but its definatly not all there...

go read this http://hyperphysics.phy-astr.gsu.edu/hbase/newt.html it's only pretty basic but it should hopefully show you enough.[/quote]

Read above.

[quote=James Bond]firstly Newton coined the term instantaneous velocity many years ago, its used a lot now-a-days too...[/quote]

Re-read my post, I said I coined the word "Velocital." I never claimed to have coined the term "instantaneous velocity.

[quote=James Bond]secondly your saying in that example Einstein view is wrong....any evidense to back it up??[/quote]

Quite a bit, actually. Anything specifically you'd like me to disprove or explain using Velocital Physics (which, as I've coined, is the study of how velocity effects classical physics)?

[quote=James Bond]I'm not sure what you hope to point out by your example but you haven't learnt relativity by the looks of it...because you are saying Einstein is wrong when in fact he is perfectly correct, because your still thinking in the Newtonian world if you believe you must be in the same interial frame as the event to truely measure its effects your 500 years behind the times.[/quote]

On the contary, re-read my example. It makes it quite clear. As to your second point, I quite clearly also stated that it's possible to calculate the events when not in the same inertial frame. However, to do this accurately, you must first understand what the observer in the moving inertial frame is experiencing. In other words, you must first calculate what the moving inertial frame observing is experiencing before you can calculate what the stationary observer is experiencing. Einstein tried to do it in reverse, he failed. The only way he could expain the indescribancies when trying it that way is through such things as "length-constraction" and "time-dialation." These things are actually not needed.

[quote=James Bond]You are correct in thinking you'll see the beam in front before you see the beam behind, but you would have to travelling at near the speed of light to notice a difference and even then, it would not be what you expected if you used Newtonian mechanics.[/quote]

Actually, the example I mentioned did state that the box car was traveling around 0.9c, I mearly forgot that part (not that it mattered what velocity it was traveling). And yes, according to the results for Einstein's example, it IS what I would expect from a basic understanding of Newtonian physics. Using Einstein's first postulate, you'd expect the result to be that both observer see both lights at the same time, regardless of the box cars relative velocity!

[quote=James Bond]Let me show you this example...

[Image]

try and get your head around that.

also as long as you know what you are doing and apply relativity correctly it doesn't matter what frame of reference you are in and whether or not you are moving or standing still...[/quote]

read above

[quote=James Bond]see muon example

http://hyperphysics.phy-astr.gsu.edu/hbase/relativ/muon.html

[/quote]

I've disproven this one several times. In fact, my first post in this thread was in regards to the muon.



With the experiment you posted there are several things to keep in mind. First that the "Life time" value they have is a "lab" value and not very likely to be accurate for a natual muon. Secondly, if you look at how muon's are created, it's easy to see how it's life time can be extended by the constant coliding with the same atmospheric building block materials that created it in the first place. In other words, the "example/experiment" proves nothing.

[quote=James Bond]I leave for a week's holiday tomorrow and if I come back and find you've posted again saying Newton and Einstein are wrong....well, I'll set my lecturers on you and you don't want them coming after you, especially Prof. Thompson.

[image]

[/quote]

I never said they were completely wrong. Newton was actually pretty close, especially at the conceptual level. Einstein had the right idea too, but just got a few things backwards (on other things, he did get wrong...at least according to Quantum Physics). If they'd like a shot as well, then they are free to do so. Just remind them that I have a keen eye for reasoning falacies, which is what their (the ones who absolutely resist the notion of things not quite being what they have spent many years of their lives beliving them to be) responses generally resort to when they come to the realization that everything they have learned in physics (from Newton - Quantum physics and beyond) is actually just a little bit different (but just enough to make dramatic changes in the way that physics is taught).

Mass doesn't exist?? What? *hits self* I seem to be solid. I'm about 54 kg. *hits desk* This seems to be here. Hell, even the ****ing keys to which I'm typing this seem to be here. MASS EXISTS Time. *looks at clock* It is now 9:04 AM PDT. In approximitly 60 seconds it will be 9:05 AM. TIME HAS PASSED. Time moves in the direction of increasing entropy. TIME EXISTS Length. I am about 1.83 m. It is about 16.2 km to school. LENGTH EXISTS Tell me, if length didn't exist, when what the hell are guys bragging about when they proclaim their schmonz is the biggest? These are not mere concepts. All things have a mass save photons. All things experience time. All things have a certain temperature. All things have a length, width, height.


No. No. No. An electron will fall to the Earth. A proton will fall to the Earth. If Earth's B field were to suddenly vanish, things will still fall to the Earth. Gravity is not a B field, not an E field. It is a fundamental force that has existed since the Big Bang. Our solar system was once a nebula of gasses, rocks, and stuff like that. They were brought together by multitude of forces, one of them being GRAVITY.


Except it's NOT TRUE. Force is not the product of mass and velocity. It never never ever will be. The product of mass and velocity is momentum.



Then how the **** do we detect muons coming from the sun?

Get ready for some bluntness. I haven't had my coffee yet. Stop trying to think that you're a wonderful physicist by thinking of all these concept about Newtownian, Relativist, and Quantum physics. You're not. Everything that you've thought about is totally wrong. Physicists have been working on these problems for centuries. There is a reason why Newton's concepts are Laws. They have withstood scrutiny time and again. Gravity is a real phenominon. It is NOT caused by pressure by any stretch of the means. The muon example is real demonstration of Relativistic speeds. Otherwise, we would have NEVER EVER detected muons from the sun. Yet we do. You are seriously sounding to the lot of us like you flunked out of high school physics several times. If you want to ponder and come up with new theories/ideas in physics, there's untold stuff about astrophysics, quantum mechanics, nuclear physics yet to be solved. But pretty much everything in the Newtonian sense is set in stone and law.

I notice my point has not been responded to.

I wonder why...?

I've just got back from my summer, job, I leave for holiday in an hour and still have to pack......please, please tell me you are doing this as a joke.

for god's sake can someone please ram home the correct facts into CaptBevvil's head if I don't get the chance.

certain things he has said are fine...the rocket example in space in the last post...its perfectly correct, but thats only because there is no fricton involved any longer...no idea what his point is though... Newton's formula are still fine in regards to it.

F=MV is not, I repeat NOT a vaild equation...its NOT dimensionally correct, ever done dimensionality testing on equations??? P=MV fine, F=MV NO, NO, NO, NO, NO!!!!
.
.
.
.
.
.
.
.
just in case you didn't hear me,

NO

this is getting longer than I thought, I can't just let things lie...

There is no atomsphere in space, move a certain distance away from a planet, ie outside its ATMOSPHERE, say half the distance between the earth and moon and space will not have an atmosphere...

I can't see why you've quoted dictionary.com or what relavence it has to your argument...I'll let someone else do that...

no you didn't, you side-stepped it.

.....bbbzzz...wrong.....some planets have very small magnetic fields and are yet none the less massive...

we can do this using Newton's laws already....you mentioned calculus, ever done a velocity-time graph?? if you know the mass of the body you can work out its acceleration, then force at any given point on the graph...without the need to use your (WRONG) F=MV equation...

ah bugger it, I'm driving down to met up with my girlfriend (1st class physics graduate), plus another Physics graduate doing his PhD, plus a first year who got top of her year this year.

If i can i'm going to get all four of us to look at this....be warned, your going to have 3 physics graduate's and 1 very clever second year looking at this, if you disagree with us then...well...there's no point in anyone posting because no matter what we say you'll still think your right when everyone else thinks otherwise.

BREE BREE BREE! IT'S FRIEND14!!!

Look dumbass, you keep saying you've proven all these theories wrong, yet you have *never* shown your proof. All you do is "explain" it. You have *never*, EVER been correct in any debate I have ever seen you take part in. You *always* get proven wrong in the end. You disappear for a while then come back to start it all over. When will you give up?

You don't seem to understand (and it's a fundamental way of thinking that most people are not use to). We have mass, but mass itself does not exist. It is a concept. In other words, you can not weigh mass, but you can weigh something that has mass. Anything that exist has a length, but length itself does not exist. In other words, you can not measure length, but you can measure somethings length. Events occur in a series of event over a period that we call time, but time itself does not exist. In other words, you can not measure time, but you can measure a series of event over a period. Again, they are all three concepts and thus would not be the perfect constants they are without being so (even though Relativity "bends" all three of them).

James Bond made the same point, so I simply answered his since he made the most points.

Nice dodge. That's not how you debate. It's only reenforcing the fact that you have no idea what the **** you're talking about.

Wow... I can't believe I started a three-page argument about physics. This has all gone way beyond any knowledge I thought I had. Perhaps I'll continue to post in this thread in three years, once I leave high school.

I'd just like to say one thing about the black holes, though:

[OPINION]
They're just superdense clumps of matter, not "mouths" of wormholes. I never said that, and I hope it wasn't implied. If it was, I take it back.
[/OPINION]

Thanks. Continue!

[QUOTE=James Bond]certain things he has said are fine...the rocket example in space in the last post...its perfectly correct, but thats only because there is no fricton involved any longer...no idea what his point is though... Newton's formula are still fine in regards to it.[/quote]

It should have be fairly obvious. There are only two things that changed in the example (side for the retro-fitting that we did to the car).

1st - The environment changed. We went from an Earth type environment to a Newtonian type enviornment.

2nd - The observations changed. A observer on Earth witnessed a car traveling at a constant velocity (hell, the driver observed that). However, the observer in space witnessed a car accelerating (again, even the driver, err pilot observed that).

Realization - Nothing within the inertial frame of the car changed! As far as the car is concerned, in both instances it was consuming the same amount of fuel at the same rate. Thus, we can conclude that the car was accelerating in both instances EVEN THOUGH there were "forces" acting against it while in the Earth type environment. THAT is what we want to know. THAT is what is important. Not the observations of the outside observers. But what was happening in the car. AND in both instances what was happening to it was identical (within the inertial frame of the car).

So, again, constant velocity on Earth is actually, constant acceleration.

If you don't understand this, then you'll never understand it at all.



See above.



I've addressed this already. The issue at hand was about pressure. Atmosphere is a portion of that BUT NOT ALL OF IT. The gas particles alone do not make up the total amount of pressure that exists IN the atmosphere. There are tons of different solid particles (dust and dead skin for one) that contribute to the total pressure. Likewise, there are dust clouds and such in space that contribute to the total pressure that exists within our solar system. I consider anything within this region an atmosphere (for simplicity sake) for better or for worse (not that it had anything to do with the point at hand, only it perhaps contributed to some of the later confusion from it).



I quoted where you quoted just to pick that one point out of your list...blah, the red harring are killing me...



No I didn't, there was nothing else to add.



Again, I used apples and oranges and you used apples and grapes...

Anyone else catching this?

I made no mentioning of the mass of the planets, stars, moons, etc. I made reference to their atmosphere. Two totally different things. Why are trying to make it out that I said something that I did not? This is what most of those "Professors" start doing once they realize that maybe, just maybe, I might be on to something.



In case you've never noticed, if you're drawing an acceleration curve, if you were to look at just one instant of time on that chart, what would you have? A point, right? And just what do you think that little point would represent if acceleration is a change in velocity over a change in time? That point, my friend, represents constant velocity for that instant OR instananeous velocity. Which is what you would have right at the moment of impact in a physics problem because Impacts are caused in an instant of time, not over a period, which is how acceleration is measured.



Again, your welcomed to it, but please leave the arguement fallacies behind. It's really starting to affect your integrity.

It's not that I haven't been correct, it's just that I have been unsuccesful at "explaining" how it all works. It's much different then most people are used to thinking (expecially those who have already had it pounded into them by various Professors).

I disappear because I have a something called "a life" and sometimes takes precidents over such debates.

It wasn't a dodge, James Bond and others have been using it quite extensively throughout the thread. I've already stated how muons are created (more specifically, where they are created in relation to the example/experiment in relevance). There was no need for me to specifically "educate" everyone on how they are created. If they don't know, then they should look it up.

[edit]
Meh, okay, for those that don't know and as was relevent to the initial statements made in the thread:

http://www.prestoncoll.ac.uk/cosmic/muoncalctext.htm

"Cosmic ray muons are created when highly energetic particles from deep space collide with atoms in the Earth's upper atmosphere. The initial collisions create pions which then decay into muons. The muons then travel down through the atmosphere and arrive at ground level with a frequency of about 1 cm-2 min-1."

"The muon has a measured mean lifetime of about 2.2ms."

Again, I just want to reiterate that the lifetime mentioned was obtained in a lab and doesn't take into account that in the example mentioned earlier, the muon is constantly coliding with more atmospheric atom, there by effectively extending it's life. The lab obtained value does not account for this.

No, it's not that. You follow these threads very closely, replying very quickly for a few pages. Then once you're finally proven wrong, *poof* you disappear.