The real rocket motion equation shows that it obeys the Classic Law of Force F=ma and not the relativistic definition F=dp/dt!
Please take a look at: http://www.geocities.com/anewlightin...n_of_force.htm

The real rocket motion equation shows that it obeys the Classic Law of Force F=ma and not the relativistic definition F=dp/dt!
Please take a look at: http://www.geocities.com/anewlightin...n_of_force.htm
Originally Posted by martillo
Just curious...
1 How do you read F=dp/dt? I guess F stands for "Force" but, what the fuck are "dp" and "dt"?
2 From which part of Relativity comes that F=dp/dt?
3 And, now that we are on it... since when Relativity deals with rocket motion (that is, as long as the rocket doesn't reaches a speed where Relativity starts being noticeable?).
Undirectly from NASA:
If I have understand the text right (I am not good in english),
Newton's 2nd law can be written in form:
F = dp / dt
so in this formula "dp = (m*v)" aka. the change of momentum
and "dt" is the change of time...
this is the way it is explained.
Those two are the same thing. Take the mass out and the change in velocity/the change in time is the acceleration. Either multiplied by mass will give you the force. Actually, what's strange is what you're saying that it actually obeys is actually how Newton defined it in Principia Mathematica. Later acceleration became it's own thing, although nothing changed. It just became easier to say acceleration instead of change in velocity over the change in time, although I do concede that it is expressed there in Leibniz notation (who discovered calculus indepently of Newton (who basically just created his own calculus first to explain motion)), however it's the same thing.
Lucifer,
It seems that you really don't know too much about Relativity.
As eternal says F=dp/dt where p=mv and m varies with velocity.
In Relativity the famous equation E=mc2 is derived directly from that formula!
Although rockets don't reaches relativistic velocities they present a big variation in mass with velocity (the fuel is expeled as it accelerates) and so the effect of the variation in mass is significant in the equations of its movement.And, now that we are on it... since when Relativity deals with rocket motion (that is, as long as the rocket doesn't reaches a speed where Relativity starts being noticeable?).
dp/dt=d(mv/dt=m(dv/dt) +(dm/dt)v
F=ma and F=dp/dt are not the same thing as silkworm says, they produce very different motion equations. If mass varies with velocity the mass factor cannot be taken out of the derivative!
Although I know Newton presented his formula in the form F=dp/dt it represent the same whenever mass is constant and Newton wasn't considering any kind of variation in mass in the phenomena he was studying. I believe that the right equation is F=ma as presented in all basic Physics texts!
So I guess "d" stands for delta...
And the reading of the formulas would be:
Force= mass x acceleration (F=ma)
and:
Force= variation of momentum / variation of time. (F=dp/dt)
I won't keep with the formulas as, admitedly, I never studied Physics beyond a very elementary level.
Anyway, I still don't understand how a rocket's motion is incompatible with Relativity. I would thank you if you tried to explain it with words rather than formulas... :?
I would be equally happy if it were done with formulas.Originally Posted by Lucifer
Martello, earlier you observed that Lucifer did not know much about relativity. That may or may not be true. i leave it to Lucifer to address if he wishes.
However, you might find you would get your point across more rapidly and painlessly if you were to follow a standard that is used in all good science writing. When you introduce an equation clearly identify and define the variables; note which units they are in. That will help to avoid much confusion.
I'm sorry Lucifer but the essential point of this thread is about the formulas!
The page I adressed at the head post is very clear in the presentation of the formulas I'm analyzing. May be you are not familiarized with the equations of the motion of a rocket (as I wasn't at first). I have found them in several sites on the web and I expect that in case of doubts everybody can do a simple search with the keywords: "rocket motion equation".
Exactly. I can grasp most formulas as long as the variables are identified properly; this is specially crytical when the formula can't be written properly by lack of greek leeters, special signs like square root, etc. How should I guess that "d" stands for "delta"?Originally Posted by Ophiolite
Concerning Relativity and Physics in general, I am not a formulaeater. As I stated in my introduction to this site, I never went to unviersity, and mathemahics are arcane to me beyond very elementary level. Never studied Calculus, my Trigonometry is a joke and my Algebra is worst (in a certain sense, my brain suffers a shortcircuit each time "x" is supposed to be any else than the first letter of "xilophon"...) I am a "man of letters" who happens to have a intuitive "knack" about how things work & a fairly competent IQ (above 98% the population, for whatever it is worth hmpf!). ITOH, I have read and assimilated hundreds of ways to express with words how things work. And so I am familiar to Relativity and "how it works", enough to be puzzled at what relation there is between rocket motion and Relativity unless when the rocket starts moving real fast and it grows noticeable that its kinetical energy (the energy we've thrown into it to accelerate it) adds to its mass and so requires addiitonal energy in order to keep accelerating. This is why I smell mumbojumbo when I'm offered formulas without explanation of the variables, and ask Martillo to explain to me the formulas to check if HE really understands them and the point he's doing... rather than trust I'm gullible enough to agree to them without, or because, don't understand them.
(BTW... I guess they're FAIRLY ELEMENTARY rocket motion formulas. Somehow Martillo suggests Scientists missed to see that they are against Relativity for the last 70 years, huh?)
Lucifer, I remain equally unclear as to what Martillo is saying. He has not, to my limited brain, presented any conflict between Newton and Einstein. All he has shown is that when we are considering rockets we need to take account of the use of fuel during firing as this reduces the mass of the rocket.
Well you don't have to be a (ahem) rocket scientist to figure that one out. But, Martello, how does that relate (ahem number two) to relativity?
I'm with Ophiolite on this one. Newton knew calculus, he was one of 2 independent inventors of calculus, which is all you would need to calculate this. Both are the same thing. Sorry.
It seems to me you are not understanding the problem properly.
It has to do with the mathematical rigourosity in the applied formulas in the movement of the rocket.
All the literature stays that the equation of motion of a rocket (which expels mass to accelerate and so the rocket itself has a mass that varies with the movement and can be expressed as a variation with its velocity) is:
F = m(dv/dt) = u(dm/dt)
You must take attention in the first equality:
F = m(dv/dt)
which clearly states that what it is considered is
F = ma
for the movement (the classic Newton's definition of force) and not
F = dp/dt = m(dv/dt) + v(dm/dt)
as Relativity Theory requires by its definition of Force.
For a rocket which has a variable mass the two relations are NOT the same.
Then it can be said that the movement of a rocket demonstrates experimentally that the relativistic formula F = dp/dt is not really valid in practice and that the classic formula F = ma is the valid one.
This is an experimental evidence (if not a proof) that Relativity Theory can be wrong and that Classic Physics can be right!
I believe it.
latehorn,
Then I encourage you to take a look at: www.geocities.com/anewlightinphysics
It worths!
I read your website, the top part began to make sense after reading it a second time, but these people are right, you have to define your variables.
When you reach "dp/dt", you don't define what "p" is... I understood though that it has something to do with the mass of the projectile varying.
"They use the conservation of momentum, right , but considering the total momentum of rocket + fuel at any moment and state dp/dt = 0."
Hmmm, so are you saying that the mass of a rocket is not changing with respect to time? Secondly when ou say fuel at any moment, the word "moment" implies that time is not changing, which might explain why dp/dt=0, but then how would that be accounting for change in mass if dp/dt is 0. I think the place you are reaching a problem is by assuming that dp/dt=0.
"It is clear that what is finally applied to the rocket to determine its movement is the equation F = ma !"
How would this be accounting for change in mass?
Oooo, I think I am starting to understand what you are saying.
would you accept that
dF/dt=dp/dt ?
If not I am plainly confused.
Nima Rahnemoon,
p is the momentum: p=mvWhen you reach "dp/dt", you don't define what "p" is...
You must take care that the equation dp/dt=0 is considered for the composite body of the rocket and the totallity of the fuel, the contained one plus the expelled one."They use the conservation of momentum, right , but considering the total momentum of rocket + fuel at any moment and state dp/dt = 0."
Hmmm, so are you saying that the mass of a rocket is not changing with respect to time? Secondly when ou say fuel at any moment, the word "moment" implies that time is not changing, which might explain why dp/dt=0, but then how would that be accounting for change in mass if dp/dt is 0. I think the place you are reaching a problem is by assuming that dp/dt=0.
Some fuel is expelled during its acceleration but for the total composed body (rocket + total fuel) dp/dt=0. This equation determines that for another body, that composed by the rocket and its contained fuel only the "thrust equation" is valid:
F=mdv/dt=udm/dt
in this equation m is the mass of the rocket plus the mass of its contained fuel and varies with time.
No, I'm saying that for the rocket (rocket plus contained fuel):Oooo, I think I am starting to understand what you are saying.
would you accept that
dF/dt=dp/dt ?
If not I am plainly confused.
F=mdv/dt
where p=mv and m is the mass of the rocket including the contained fuel.
This implies that F is not equal to dp/dt=mdv/dt+vdm/dt.
I don't think that anyone in this thread has understood the physics involved here. The relation F=dp/dt is a statement of Newton's second law in nonrelativistic physics. Relativity does generalize it to F^u=d(p^u)/dT (T=proper time, F^u=4force, and p^u=4momentum), but that is beside the point. The variation of the mass of a system with time has nothing whatsoever to do with the idea of relativistic mass, which states that mass varies with speed.
Talk about ironic.martillo: It seems that you really don't know too much about Relativity.
No, it isn't. You can't derive a relativistic relation from a nonrelativistic one.As eternal says F=dp/dt where p=mv and m varies with velocity.
In Relativity the famous equation E=mc2 is derived directly from that formula!
Einstein's original 1905 derivation of E=mc^2 is here:
http://www.fourmilab.ch/etexts/einstein/E_mc2/e_mc2.pdf
My old friend quantumdude! Wellcome.
Not at all! Force as F=dp/dt is defined that way only in Relativistic Physics. In Classical Physics F=ma. You can see this in any basic text of Physics!The relation F=dp/dt is a statement of Newton's second law in nonrelativistic physics.
By the way, please don't introduce here tensorial notation that is totally unnecessary and confuse the simple reasoning presented here.
As a rocket accelerates its mass (contained fuel included) varies and the two equations:The variation of the mass of a system with time has nothing whatsoever to do with the idea of relativistic mass, which states that mass varies with speed.
F=dp/dt=m(dv/dt)+v(dm/dt) (the relativistic one)
and
F=ma=m(dv/dt) (the classic one)
give very different results!
I think you have recently entered here and that is you that don't understand the Physics involved here. You should read more carefully earlier posts particularly the head post.I don't think that anyone in this thread has understood the physics involved here.
No, you are wrong. Look in a notsobasic texbook such as Goldstein and you will see that F=dp/dt is part of nonrelativistic physics.Originally Posted by martillo
Here is an online textbook at the same level as Goldstein:
Classical Mechanics
Right from the introduction it says:
"The emprical evidence has shown that the motion of a particle in an inertial system is correctly described by Newton's second law F=dp/dt, whenever it is possible to neglect relativistic effects."
If you read the book (or any comparable textbook) you will learn that F=dp/dt is a nonrelativistic relation, and that F=ma is inadequate for doing nonrelativistic physics on systems with timevarying mass.
But it is necessary to differentiate between Newton's second law in nonrelativistic physics and in SR.By the way, please don't introduce here tensorial notation that is totally unnecessary and confuse the simple reasoning presented here.
No, I understand the physics just fine. It's all very basic, and I learned it as an undergraduate.I think you have recently entered here and that is you that don't understand the Physics involved here. You should read more carefully earlier posts particularly the head post.
The opening post is wrong, just like all of your other posts.
Quantumdude,
I believe there's no better example of timevarying mass than a rocket and as I said at the head post in all the web pages I have found (in an extensive search) it is derived the equation of motion of a rocket as:If you read the book (or any comparable textbook) you will learn that F=dp/dt is a nonrelativistic relation, and that F=ma is inadequate for doing nonrelativistic physics on systems with timevarying mass.
F=m(dv/dt)=u(dm/dt) (the "thrust equation"!)
Then you can see the central point of the problem of this thread: just look at the first equality and you will find that it is stated that the motion (movement) of a rocket follows the equation F=ma and does not follow the equation F=dp/dt which will give very different results!
That's the point.
F=ma is the classic formula which becomes equal to F=dp/dt only for constant mass. This is the formula that can be found in the majority of the basic texts books regarding that sometimes it is cited that Newton originally wrote it as F=dp/dt but I strongly believe Newton never considered timevarying masses problems (rockets didn't existed at his times). This cite is only an introduction to the proposed F=dp/dt formula of Relativistic Physics.
I have wrote:
You wrote:As eternal says F=dp/dt where p=mv and m varies with velocity.
In Relativity the famous equation E=mc2 is derived directly from that formula!
The equation is derived directly from the definition of Kinetic Energy and using the relativistic definition of force F=dp/dt.No, it isn't. You can't derive a relativistic relation from a nonrelativistic one.
That thrust equation comes from Newton's second law, which in its most general nonrelativistic form is F=dp/dt. If you read real books written by real scientists, instead of only internet webpages, you would have seen that.Originally Posted by martillo
I gave you a link to an online graduate level textbook that explains all of this. But in the last hour I have gone through my undergraduate books and found that it is there too. You can find all of this information in the following books:
Fundamentals of Physics, by Halliday, Resnick, and Walker
Vector Mechanics for Engineers, by Beer and Johnston
Mechanics, by Symon
The central problem of this thread is that you are confused about classical mechanics and about relativity. Nonrelativistic physics says that the rocket motion is determined by F=dp/dt. Period.Then you can see the central point of the problem of this thread: just look at the first equality and you will find that it is stated that the motion (movement) of a rocket follows the equation F=ma and does not follow the equation F=dp/dt which will give very different results!
That's the point.
That is indeed what he said. The exact (English) statement of the second law, in Newton's own words, is as follows:F=ma is the classic formula which becomes equal to F=dp/dt only for constant mass. This is the formula that can be found in the majority of the basic texts books regarding that sometimes it is cited that Newton originally wrote it as F=dp/dt
"The rate of change of momentum of a body is equal to the resultant force acting on the body and is in the same direction."
So now you claim that Newton didn't understand Newton's second law?but I strongly believe Newton never considered timevarying masses problems (rockets didn't existed at his times).
Look, you don't need to have a rocket to consider a system with timevarying mass. Sailors who lived long before Newton knew that you could increase a ship's speed by throwing weight off. Newton was undoubtedly aware of this. The physics of that situation is no different than the physics of your rocket.
No. Newton's second law in relativistic physics is exactly what I said it was, in 4vector form. That is not the same thing as Newton's second law in 3vector form. The relation you are talking about conforms to Galilean Relativity and contradicts Special Relativity. That much should be obvious by the fact that the derivative is with respect to coordinate time. In relativity, temporal derivatives are always with respect to proper time.This cite is only an introduction to the proposed F=dp/dt formula of Relativistic Physics.
No, it isn't. If you cite the references where you think you have seen this derivation, I will explain to you why you are mistaken.The equation is derived directly from the definition of Kinetic Energy and using the relativistic definition of force F=dp/dt.
Now something that is derived from F=dp/dt is the law of conservation of nonrelativistic momentum. If you deny that F=dp/dt is part of classical physics then you deny the theoretical basis for momentum conservation in nonrelativistic physics. Such a point of view is obviously wrong.
Please, martillo, do yourself a favor and study some physics. I am getting tired of doing your homework for you, and I am getting equally tired of repeating myself. If you would just take the time to do some research you would understand what I am telling you.
Quantumdude,
As always you become agressive and it is difficult to discuss with you...
Anyway,
Yes I deny.If you deny that F=dp/dt is part of classical physics then ...
In Classical Physics F=ma.
Even if mass varies!
I'm not confused about anything. You would want that but it is not. It's you that cannot agree with me because you believe in Relativity so much that you are capable of making any kind of concession in Mathematics and Physics rigourosity just to mantain it floating. You are bline and stubborn what is perfect for a mentor of the well known closed forum www.physicsforums.com isn't it?The central problem of this thread is that you are confused about classical mechanics and about relativity.
You say this but it is not what the web says. Demonstrate this, give me the derivation of the real motion of a rocket from basic principles of Physics reaching that equation. Show us if you can!Nonrelativistic physics says that the rocket motion is determined by F=dp/dt. Period.
Let me see if I can summarize things a bit:
When a (conventional) rocket operates, it looses total mass in the form of burnt and expended fuel. (In the common tongue, it gets lighter.)
As the rocket accelerates, it gains mass and looses length from that movement (per Lorentz). (In the common tongue, it gets heavier and shorter but not by much.)
However, the effects of relativistic gains in mass or loss in length are negligible at speeds attainable by our technology. (Lorentz transformations don't mean much in real life.)
Yeah, and ... ?
The current reality is we don't have computers powerful enough to calculate trajectories of spacecraft (like we sent to Mars, Venus and such) according to relativistic formula. NASA uses classical Newtonian physics to rendezvous our spacecraft with Saturn and so on. Out to the orbit of Pluto, the differences are negligible.
So, Matillo; what's your point? What should I glean from your statements to enrich my life or correct my thinking?
Archie,
Forget any relativistic effect on the rocket, this is not the point!
The point is that during its acceleration the rocket, with its contained fuel included, looses mass as expelled burned fuel. Then if we call m the mass of the rocket plus its contained fuel and m varies with time it is very different to consider the motion equation of the rocket as F=dp/dt (the relativistic one) than F=m(dv/dt)=ma (the classic one).
I have made an extensive search on the web and the second is considered the valid one.
This is an experimental proof that the relativistic definition for force is wrong and that the classic one is right!
How difficult is this subject to not be understood properly?
It is not difficult, the problem is that it disproves Relativity which is sacred for you and your minds don't like to accept it!
Just that.
Okay. As I said, at the speeds our technology can attain, it really doesn’t matter.Originally Posted by martillo”Motion equation”? I’m not sure what you mean by ‘motion equation’. The formula F=ma refers to the force required to accelerate the body (rocket) to the velocity in question and – simultaneously – the kinetic energy of the moving body (rocket) itself. Which is oddly also calculated by E= (.5 (m*v^2)). I fail to see your connection of work performed displacing relativity.Originally Posted by martilloOh? Other than you, who thinks we can discard relativity?Originally Posted by martilloI don’t see any connection, actually.Originally Posted by martillo
Yeeeaaah…. okay...Originally Posted by martillo
Just so you understand, no scientific theory is 'sacred'. It either explains certain conditions and makes predictions to be tested, or it doesn't.Originally Posted by martillo
So what you want me to understand is Relativity is not a valid concept? You're saying time does not pass slower in an accelerated environment, gravity does not affect light and light speed is not constant to the observer? Is that it?
Archie,
Your answers don't deserves my response. After some time at forums I know those kind of thoughts enough...
Martillo, your surrender is accepted. You may keep your sword, but I fear you may hurt yourself with it.Originally Posted by martillo
I really didn't realize there were any antiRelativists left. Life is just full of surprises...
The only thing making this difficult is your unwillingness to be reasonable.Originally Posted by martillo
No. Consult a textbook on classical mechanics. Any of the references I gave you in my last post will suffice.Yes I deny.
In Classical Physics F=ma.
Even if mass varies!
You are confused about a great many things. I already knew that you understand nothing about relativity, and now it is becoming clear that you don't understand nonrelativistic mechanics either.I'm not confused about anything.
I cannot agree with you because you are wrong. You are the one who denies all logic and evidence to keep your crackpot point of view floating. You would even go so far as to have us believe that Newton didn't even understand the laws that bear his name. It would be funny, if it weren't so sad.You would want that but it is not. It's you that cannot agree with me because you believe in Relativity so much that you are capable of making any kind of concession in Mathematics and Physics rigourosity just to mantain it floating.
And as for mathematical rigor, the only one of us who has been trying to get that straight is me. You wouldn't even listen to my attempt to point out the distinction between F=dp/dt in 3vector form, and F^u=dp^u/dT in 4vector form. You simply dismissed it for no good reason. But as I pointed out to you, if you compare the two it becomes obvious that the first relation is nonrelativistic. For one thing the time derivative is with respect to coordinate time, which you wouldn't see in the relativistic version of Newton's second law. But then again I fear that all of this is lost on you because of your complete lack of comprehension of relativity, and your stubborn unwillingness to learn it properly.
I see you still have a case of sour grapes over our rejection of your submission to our Independent Research Forum. Your submission was rejected because it is nonsense. It is nonsense for the reasons I gave you. You would be well advised to use the critique as a starting point to learn some real physics.You are bline and stubborn what is perfect for a mentor of the well known closed forum www.physicsforums.com isn't it?
HAHAHAHAHA!You say this but it is not what the web says.
Is that a fact? Let's see about that.
These websites disagree with you.
http://en.wikipedia.org/wiki/Newton's_laws_of_motion
http://hyperphysics.phyastr.gsu.edu/HBASE/newt.html (click on "Limitations")
http://www.grc.nasa.gov/WWW/K12/airplane/newton2.html
And there are many, many more. Now one may ask, "How did you find those websites, quantumdude?" I'll tell you: I typed "Newton's second law" into Google, and those 3 websites were on the first page of hits.
So martillo, in your searching did you somehow miss these websites or have you simply ignored them?
You really need to stop using the web as your primary resource, and start reading books for a change.
Martillo, I already passed my exams and I graduated from school. I don't need to be tested by you, of all people. You keep blathering on as if this were some debatable point. It isn't. The matter is settled, you just don't understand it.Demonstrate this, give me the derivation of the real motion of a rocket from basic principles of Physics reaching that equation. Show us if you can!
I already gave you references to follow. Do your own homework.
Quantumdude,
I have studied the subject some more and have realized that you are right in one point. Newton originally stated F = dp/dt and as you says Classical Physics have that law with that formulation.
I realize now that the situation of Physics is worst than I thought. Even Classical Physics is wrong in that formula!
Then is my proposition now that the valid equation for force is F = ma even when mass varies and not F = dp/dt!
I have changed the web page about my considerations of the movements of rockets to express this.
This is getting better...
Well I had hoped that I would come back to find that martillo's pot is no longer cracked, but alas it was not to be.
That's progress.Originally Posted by martillo
Whoops, spoke too soon.I realize now that the situation of Physics is worst than I thought. Even Classical Physics is wrong in that formula!
No martillo, classical physics is not wrong in its domain. If you don't believe that nonrelativistic rockets are accurately described by F=dp/dt then you should try asking people who really work with rockets.
http://www.grc.nasa.gov/WWW/K12/airplane/newton2.html
Then your proposition is wrong. If you're so interested in "real rocket motion" then take it from the "real rocket scientists" at NASA.Then is my proposition now that the valid equation for force is F = ma even when mass varies and not F = dp/dt!
Good grief.I have changed the web page about my considerations of the movements of rockets to express this.
This is getting better...
Quantumdude,
I have already done this.If you're so interested in "real rocket motion" then take it from the "real rocket scientists" at NASA.
The NASA's link you provided is not new for me and I suggest you to take a look at the following of the same site that shows the considered thrust equation for rockets:
http://exploration.grc.nasa.gov/educ...et/rockth.html
You can see there that the equation is the same as those present at the links I provide at the head post except for the component of the pressure of the expelled gases.
This means they consider the same derivation that is clearly shown at the pages I provide.
This means that also the NASA uses the same F = ma equation for the motion of rockets!
Incredible but certain.
No, they don't. They even say so in the website you just presented. Click on "prev" to see the previous page. They clearly state that Newton's second law is F=dp/dt and then they derive the thrust equation from that. Of course I already told you that on the last page of this thread, but now you can see it at a website that you provided yourself.Originally Posted by martillo
As I said, you need to consult a textbook on classical mechanics. And to get this thrust equation you will need to consult a textook on fluid mechanics. The information you need to resolve your confusion is readily available, but you do have to read it. Medicine doesn't work unless you take it.
Quantumdude,
As I say at the head post, what they really do is to apply dp/dt = 0 for the composed body of the rocket and the totallity of the fuel, the contained and the expelled ones. After that they derive the equation of motion of the body of the rocket and its contained fuel only (mass m here)obtaining the thrust equation wrotten as:They clearly state that Newton's second law is F=dp/dt and then they derive the thrust equation from that.
F = m(dv/dt) = u(dm/dt)
It is obvious that what they are considering at the end for the rocket and its contained fuel is F = m(dv/dt) =ma
and not F = dp/dt = m(dv/dt) + v(dm/dt) which would give a very different result.
The rocket with its contained fuel obeys the equation F = ma!
I can't believe you're still going on about this. Just look at the top of the following webpage:
http://exploration.grc.nasa.gov/educ...t/thrsteq.html
They clearly state the definition of force that they are using. Could it be that they just forgot about it later? Of course not!
If you let the momentum of the rocket + contained fuel be P<sub>R</sub> and the momentum of the expelled fuel be p<sub>F</sub>, then sure you can write down the momentum balance:
dP /dt=dp<sub>R</sub>/dt+dp<sub>2</sub>/dt=0
Now of course you can plug in expressions for p<sub>R</sub> and p<sub>F</sub> and solve for ma. But that doesn't change the fact that Newton's second law for any object is F=dp/dt. This is explained clearly in any of the references I gave you. It is most clearly laid out in Symon's book.
And now I've got another reference: Introduction to Fluid Mechanics by Fox and MacDonald (any edition will do). They start the analysis of every problem with the correct form of Newton's 2nd law.
Martillo, it is simply not the case that you have discovered something so fundamentally wrong with classical mechanics. You really need to try to study some more.
Quantumdude,
You tells about what books says and I'm considering data that shows what I interpret a discrepancy.
I know is a too trivial subject for you, it is not for me.
I will look for more data to analyze...
martillo
F=dp/dt is the classical definition
newton come up with that concept and said thats what force is. but p=mv and v/t=a in classical physic
therefor when V is low u can use F=mv/t=ma
quantumdude,
Yes it is!Martillo, it is simply not the case that you have discovered something so fundamentally wrong with classical mechanics. You really need to try to study some more.
I have discovered something fundamentally wrong in classical mechanics!
I'm sure now.
I recognize I was wrong believing that Newton and Classical Physics stated the Equation of Force as F=ma.
They stated F=dp/dt and what I have to say now is that they are both wrong!
The true Equation of Force is F=ma.
The equation of motion of rockets used by everybody shows that.
My analisis made at the page I cited at the head post demonstrate that.
NOTE: I had to edit the page since it changed, the page now is: http://www.geocities.com/anewlightin...n_of_force.htm
martillo, thats a big fat lie, the true formula is the one newton startded with
F=dp/dt
the other is force in classical physic
Zelos,
Is not a big fat lie but a simple discovery.
The real equation of Force must be F=ma.
the thing is, F=dp/dt is newtons own deffinition. but he derivated it to f=ma and in reality its so until mabout 1/3C then relativiistic gets important.
but if u think on it like this
F=ma
if F is constant and is applied during the time t then we get
F dt=mat
and at=dv if v0=0 then
F dt=m dv
and *f we devide by time then we get
F = m dv/dt
You are so confused as the way you write!
im not confused, but ure apperently ont smart enough to understand very simple math that even newton understood
REAL ROCKET MOTION EVIDENCE, continued:
Senor Martillo (deja vu):
I'm not much on math, or predictions.
Fortunately, both Newton and Einstein, were, in that order.
And, I have learned that there are two kinds of people relative to Newton and Einstein. Those who understand them, and, those who don't.
I have also learned that I don't have to do the math or predictions in this realm, because that's already been done. And checked out by people who understand them. Done by Newton and Einstein. Fathomed, sounded and checked by exemplary people such as quantumdude and Zelos (this time)  to name a few in particular.
A lot of the foregoing I transferred from another forum, with some modification, the arguments were similar enough to be included here. Just as your arguments, Mr. Martillo, are likewise familiar...
Cactus Critter (on another forum) wrote:
"It has been about 55 years since I graduated from Ohio State University with a B.Sc. in Physics. Therefore, it has become difficult at times for me to remember what I was taught in college and what I have gained by selfstudy.
My remembrance is not that Einstein equated accelerated motion with gravity.
Rather, he stated that one cannot tell the difference between acceleration due to gravity and acceleration due to being accelerated, say in an enclosed elevator.
To me, that doesn't open a discussion of things exotic or mystical.
It's a simple statement of fact and Einstein was right."___________________________________________ ___________
Can't say it any more clearly and briefly than that.
Had I found this post earlier I would have said the exact equivalent (no puns intended) of what Cactus Critter said, though probably not with the elegant simplicity of Cactus Critter.
The pink snow blowing lengths that some folks (in this case, one in particular <Rocketpan?>) are willing to stretch out in order to oneup or otherwise usurp Einstein (and/or Newton), when he's not being overtly bashed, remarkably continue keep on snorting and rolling in.
Misner, Thorne and Wheeler's *GRAVITATION has a lot to do with this 'New Age departure', amounting to a political platform from which to misrepresent in order to then 'gainsay' Einstein (did not 'predict the Big Bang' hypothesis, for example. He was back to working on the previously abandoned 'biggest blunder of my life', until his perishment at Princeton, May 1955. Moreover: Observations of an accelerating expansion of the universe have only begun to be reported <and, have any of you whippersnappers ever heard of Carl Sandage? Well yer gonna: get used to it>...)
'Limitless are the number of apparently reasonable conclusions that can be based on a completely false premise'.  Anon
Dear dear Mr. Martillo:
Relative to gravitation, the term 'force' (F) has yet to be identified.
The same is true of the causation of the so called (much maligned) 'gravitational curvature of space'. The 4D spacetime continuum seems to have been completely left out.
The series of posts in this thread deserves  as a collective  to be massively posted, published and distributed as an exemplary case of abject refusal to see the light.
Of course Einstein's work  like that of Newton  will evolve with improvements, but not by way of the awry avenues demonstrated in this tribute to glorified futility  portions of which resonate with something more like beguiled evangelism than scientific demeanor or method.
Dear dear Mr. Martillo (mi caro):
Speaking of 'accleration, rocket ships', Guy Murchie's MUSIC OF THE SPHERES features an exquisite ink drawing of a rocket ship hovering just above the launch pad at full throttle, with a huge spiderweb connecting the ship to the ground. For this reason, with regard to statements of the obvious about inertial frames of reference and contortions of the interchangeability of reference  and coordinate  systems taking difference with and disembarking from Einstein's SR & especially GR, Cactus Critter, quantumdude, Zelos, Broomfondel or myself might draw you a picture. Whereas, Guy Murchie has already splendidly done just that.
With the self explicit exception of those on or in agreement with this  Rocketman inspired  thread who prove not to need to heed this advise, the rest of you baroque dissenters and vacant, sloe eyed, filigreed innovators may as well go back to Physics 101 and do your forsaken homework, for a change. Mr. Martillo sets an exemplary standard of who this reply is addressed to. Speaking of addresses, Truly Yours recommends the following  for Martillo to learn from and for the likes of quantumdude and Zelos to correct, improve and/or contribute to.
http://forums.delphiforums.com/EinsteinGroupie
kraziequus@yahoo.com
"If I knew the beginning and the end, I'd put everything else in the middle."
 Ralph Waldo Emerson
Thank you, CactusCritter, Sir. We all needed that (for various reasons?).
Thanks also to quantumdude and Zelos for straightening out the imperiled geodesics and etceteras... Keeping the forum spiffy. Policing the remarkably unrelenting thoughtpolice...
While you cited highrollers  you know who you are  are at it, pay particular heed to the difference between inert and heavy mass values, until it sinks in that  until further notice  *there isn't any discernible difference (Refer, Roland Von Eotvos, and others beating the same path, since. Not unrelated to the 'curvature of spacetime' being a straight line 'geodesic' caused by the unaccounted for, ominidirectional acceleration of 4D matter).
*Behold the acelerating heart of General Relativity, that would be judged as having been a passing vogue, 'because Einstein and his work were such a novelty at the time (paraphrased)'.
Sorta reminiscent of the Big Bangologists pardoning themselves for their inability to find a common center from which the  newly discovered  expanding universe recedes, 'because the universe is so big'. (Big enough to get that lost & found in spacetime, we may only surmise?)
Let's hearhere & now it then, for Newton's antiquity and how high the  'New Age'  time is to renovate his furniture and flip his  semi impeccable  house. (rotflmao.)
Vroomfondel: Only four replies as of 7/28/06. Could it be that Mr. Martillo has retired from the malaise? Has El Maestro balked the terrific opportunity you've so generously extended? Perhaps Mr. Martillo (Misner, Thorne & Wheeler's GRAVITATION?) is right, and Newton and Einstein are wrong? Truly Yours, if no one else, is entirely prepared to take a subordinate seat in Mr. Martillo's mothershipping classroom, whenever he may provide a greater reason to be there, than in any other mental institution of higher education?
Dear Mr. Martillo. Is it to be understood that (however belatedly) you have retired from the podium? You may indeed improve on Newton or Einstein, Sir. You still have the floor (if not the launch pad?) at broomfondel's generously prepared table. Even I, without mathematical acumen or predictions, have acquired considerable education, due to your indomitable tenacity, in the true spirit of Don Quijote. (Es vale y Simone, Senor). Is there no more evidence of real rocket motion?
C'est fini? (Ya?)
Thank you for reading this missive.
That Rascal Puff,
I'm not in any podium and no privileged place and I'm nobody, I'm very conscient about this.
It is not easy to criticize famous personalities particularly those currently called genius of the humanity but nobody should feel this way, nobody is infallible! Not anyone! Not even you and me and even Newton and Einstein! They were humans and please let them make a mistake!
I make mistakes everyday but this does not prevent me to make a good job or a good work, I must just recognize the errors fix them, correct them and go on.
The first thing everyone must agree is that nobody in our world never make a mistake. If such a one could exist we would nominate him the King of the planet and every problem would have been solutionated.
There are no such ones.
By the way, I'm not a unique one against Einstein, the web is full of people that disagree with him or just don't believe in his theories although they don't have the right alternative.
I feel I have made some discoveries in Theoretical Physics which leave to the right alternative and I'm convinced they are right and true although many proves and demonstrations need to be done.
I worked hard, I have participated in web physics forums, I have found some mistakes that I corrected but I strongly believe the new theories are right so please let me defend them.
There is a chance for me to be right...
martillo i dont want to be harsh, but there is no chance, your theory goes against all experimental data from the last 100 years. no other theoretical theory does that, they often have nothing to support them yet, but nothing that goes against them yet either unlike yours
here ie a exemple for a electrons motion
experimental data:
V=0,99C
p=1,84*10<sup>21</sup>
relativity prediction at v = 0,99C
p = 1,83*10<sup>21</sup>
your rpediction according to classic at v = 0,99c
p=2,59*10<sup>22</sup>
in this exemple your idea is 7 times of the experimental data, while relativity is 0,5% of, this little differens can be taken as measurment error or that the calculator or something werent powerful enough or something, wich should we belive, the one where prediction is 7 times(600%) off, or the one with 0,5% off? hard choice istnt it?
Dear Martillo:
You're a darn good sport and I respect you, and your work. You may indeed  at any time  improve on any of the greater or lesser known works.
I wish I spoke Spanish as well as you do English.
Che Bueno Senor. From what may be drawn from your posts, you are a strong, good and fair person  a tried and true inspiration to all sensitivities. Thank you for being.
That Rascal Puff,
Thank you. I wish something on the new theories could be good for you or at least could give an inspiration for something good...
Zelos,
How can you say my theories predict a different p while they have the same formula for p:
p=mv
Your comments are really out of place!
Nothing more wrong than this. My theories agree with all experimental data, they just disagree with some of current theories.martillo i dont want to be harsh, but there is no chance, your theory goes against all experimental data from the last 100 years.
quite simple to answer, becuase your mass dont increase as speed increaseHow can you say my theories predict a different p while they have the same formula for p:
p=mv
nope once again, if i were compadible with experimental data it would explain why subatomic particles of higher generations and other quark composings have a longer halflife when they are moving with speeds close to C than if they were at rest. Your theory says against time dilation that is predicted by relativity and that have been proven to be a extremly exact formula for the timedilation they have observed on this particlesNothing more wrong than this. My theories agree with all experimental data, they just disagree with some of current theories.
Zelos,
OK, give me the link to your experiment and I will tell you what is going wrong.quite simple to answer, becuase your mass dont increase as speed increase
The anser is in Appendix B  part C.nope once again, if i were compadible with experimental data it would explain why subatomic particles of higher generations and other quark composings have a longer halflife when they are moving with speeds close to C than if they were at rest. Your theory says against time dilation that is predicted by relativity and that have been proven to be a extremly exact formula for the timedilation they have observed on this particles
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