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Natural Science Forum / Physics / General Physics / July 2008There is no relationship between gravity and inertia
An object subject to a gravitational field must accellerate. That is is must constantly increase speed. This is easy to see because when the object is first "dropped" gravity causes it to change speed, so at every point along the way gravity is operative and so causes an increase. Only if gravity operated only at the beginning and then was turned off would we expect the speed not to change. Consider pushing so hard on an object as to get a pressure that is equal to the pressure felt by an object resisting the pull of gravity. Of course we will move this first object at the same changing speed as a body in a gravitational field would move if the "pressure" of the supporting surface is removed. What's so mysterious about that? (And why is there inertia at all? why does the body resist? Because speed equals increased mass and increased energy (yeah, same thing) and these are not free.) We intentionally supply an accelleration pressure of one G and then are amazed that gravity and accelleration seem identical---but we are the ones who made it come out that way. > We intentionally supply an accelleration pressure of one G and then > are amazed that gravity and accelleration seem identical---but we are > the ones who made it come out that way. No, Nature did by dictating that all objects, regardless of mass, should fall at the same rate in a uniform gravitational field. > > We intentionally supply an accelleration pressure of one G and then > > are amazed that gravity and accelleration seem identical---but we are [quoted text clipped - 3 lines] > of mass, should fall at the same rate in a uniform > gravitational field. I always wondered why anyone would question that. If you drop two ten pound rocks why should they fall faster if they are hooked together. My point was that if you have a ten pound object sitting on the shelf there is a constant ten pound pressure on the bottom of the object---- Ok now put the object in space and subject one side of the object to the same ten pound pressure. To the "inhabitants" of that object it must feel exactly the same as to the inhabitants of the object on the shelf. (and to outside observers the second object will change speed). So where's the problem or the amazing congruence? >>> We intentionally supply an accelleration pressure of one G and then >>> are amazed that gravity and accelleration seem identical---but we [quoted text clipped - 13 lines] > shelf. (and to outside observers the second object will change > speed). So where's the problem or the amazing congruence? Put an object weighing 5 lb next to a 10 lb object in a uniform gravitational field. The 5 lb object has a force of 5 lb on it, while the 10 lb object 10 lb. Different forces. Yet they will fall at the same rate. This can only happen if gravitational mass is equal to inertial mass. It didn't have to be so. Consider the types of mass that we recognize. There's the mass that creates a gravitational field, the M in the formula F = G*M*m/r^2 Then there's the mass that responds to the gravitational field, the small m in the formula. That is, the value we assign to a body that "hooks onto" or "interacts with" the field produced by the big M. There's no reason why these couldn't have been different. Then there's the inertial mass, the one that goes into the formula F = M*A That determines the reaction force in response to a given acceleration (inertia), or the acceleration that would result from the application of a given external force. Again, there's no particular reason why this mass should be numerically equal to the other two. It just is, and that's Nature's doing. > >> "Osmium" <Rusht...@aol.com> wrote in message > [quoted text clipped - 52 lines] > > - Show quoted text - "Put an object weighing 5 lb next to a 10 lb object in a uniform gravitational field. The 5 lb object has a force of 5 lb on it, while the 10 lb object 10 lb. Different forces. Yet they will fall at the same rate. This can only happen if gravitational mass is equal to inertial mass. It didn't have to be so." Yes it did. Put ten 4 lb objects side by side in a gravitational field. They all fall at the same rate. Now connect them with a wire so they are one 40 pound object. Why would anyone expect them to fall faster? >>>> "Osmium" <Rusht...@aol.com> wrote in message >> [quoted text clipped - 67 lines] > so they are one 40 pound object. Why would anyone expect them to fall > faster? You don't expect them to because your experience tells you that they don't. Yet pre-Galilleo, people *did* expect heavier objects to fall faster than lighter ones. This was Aristotelean physics, which drew its conclusions from "logic" rather than experience. > An object subject to a gravitational field must accellerate. That is > is must constantly increase speed. [snip crap] 1) Your a.s. 2) A chair. 3) Bullshit. > We intentionally supply an accelleration pressure of one G and then > are amazed that gravity and accelleration seem identical---but we are > the ones who made it come out that way. 1) Equivalence Principle. http://en.wikipedia.org/wiki/Equivalence_principle 2) Idiot. http://www.albinoblacksheep.com/flash/youare <http://www.apa.org/journals/features/psp7761121.pdf>  SignatureUncle Al http://www.mazepath.com/uncleal/ (Toxic URL! Unsafe for children and most mammals) http://www.mazepath.com/uncleal/lajos.htm#a2 > > An object subject to a gravitational field must accellerate. �That is > > is must constantly increase speed. [quoted text clipped - 21 lines] > Uncle Alhttp://www.mazepath.com/uncleal/ > �(Toxic URL! Unsafe for children and most mammals)http://www.mazepath.com/uncleal/lajos.htm#a2 Uncle Al, Aren't you the idiot now? The Equivalence principle is exactly what I was saying in my post. It's just so obviously true that I wonder about everyone discussing about why gravity and inertia are the same. Maybe I can explain this in baby talk to you. "When you push on an object with the same force as the object is subjected to sitting on the earth "object experiences the same force". It's a truism. You can see the math but you "can't see the forest for the trees." See my other posts why "Quantum wierdness" is not wierd but obvious, and why falling objects should "obviously" not fall at different speeds if of different weights. Maybe it's good I don't know math---it does not blind me to the obvious. > > > An object subject to a gravitational field must accellerate. �That is > > > is must constantly increase speed. [quoted text clipped - 17 lines] > > http://www.albinoblacksheep.com/flash/youare > > <http://www.apa.org/journals/features/psp7761121.pdf> > Uncle Al, Aren't you the idiot now? The Equivalence principle is > exactly what I was saying in my post. It's just so obviously true > that I wonder about everyone discussing about why gravity and inertia > are the same. [snipc rap] Idiot. The Equivalence Principle is postulated and unnecessary. ANY decent theory of gravitation can be written without it, including General Relativity. The only interesting part of gravitational physics is then the disjoint divergence - those bodies whose centers of mass do *not* locally vacuum free fall along parallel trajectories. One empirical falsification and it's a different ballgame. Nobody is keeping this a secret, idiot. Everybody knows how to violate the EP: Ashtekar for General Relativity, teleparallel gravitation overall, http://www.ift.unesp.br/gcg/tele.pdf "In other words, gravitation becomes a chiral interaction, a property that may eventually have important consequences at the microscopic level." http://arxiv.org/abs/0801.4148 <http://www.scielo.br/scielo.php?pid=S0103-97332004000700014&script=sci_arttext> http://arxiv.org/abs/0801.4566 Chiral Gravity in Three Dimensions http://arxiv.org/abs/0806.3082 Anomalous CMB polarization and gravitational chirality http://arxiv.org/abs/0806.2821 Fermions in Loop Quantum Cosmology and the Role of Parity http://arxiv.org/abs/0805.1294 "Parity-violating macroscopic force between chiral molecules and source mass" The relevant experiments are run to high sensitivity in existing equipment by unchanged validated protocols, http://www.mazepath.com/uncleal/qz4.pdf technical readout http://www.mazepath.com/uncleal/lajos.htm#a2 doable in an undergrad lab Somebody should look. Untutored idiots need not apply. SignatureUncle Al http://www.mazepath.com/uncleal/ (Toxic URL! Unsafe for children and most mammals) http://www.mazepath.com/uncleal/lajos.htm#a2 > Uncle Al, Aren't you the idiot now? The Equivalence principle is > exactly what I was saying in my post. It's just so obviously true [quoted text clipped - 9 lines] > Maybe it's good I don't know math---it does not blind me to the > obvious. Throw a 5 lb mass up in the air. When it gets to the top.. guess what.,, it has 0 force for a very brief moment. and then the force increases from then on. Because of the energy differences above and below. above has the higher energy (more freedom of motion) and below has less freedom of motion. the difference in the energy is what causes the "push" downward. and also causes the slowing down to reverse the upward motion into a downward motion and then of course.. the larger mass "gained" more of that energy difference on the way down because it used more of it simple as that.. Crazy.. but not stupid unless you don't want to think about it. :) SignatureJames M Driscoll Jr Spaceman >> Uncle Al, Aren't you the idiot now? The Equivalence principle is >> exactly what I was saying in my post. It's just so obviously true [quoted text clipped - 13 lines] > When it gets to the top.. guess what.,, it has 0 force > for a very brief moment. No, it has zero vertical velocity for a brief moment. It's still being accelerated downward by gravity. > and then the force increases from then on. No, the force stays the same. The velocity increases in the downward direction. > Because of the energy differences above and below. > above has the higher energy (more freedom of motion) > and below has less freedom of motion. That's crap. Freedom of motion, whatever you think that might be, has nothing to do with it. It's strictly gravitational potential in the Earth's gravitational field. > the difference in the energy is what causes the "push" downward. > and also causes the slowing down to reverse the upward motion > into a downward motion and then of course.. the larger > mass "gained" more of that energy difference on the way down > because it used more of it simple as that.. Used more of it? Potential energy is strictly a matter of position in a field, coupled with whatever "charge" the field corresponds with. For gravity it's mass. > Crazy.. but not stupid unless you don't want to think about it. Sometimes, apparently, it is crazy even if you do think about it, depending of course upon who is doing the thinking. >>> Uncle Al, Aren't you the idiot now? The Equivalence principle is >>> exactly what I was saying in my post. It's just so obviously true [quoted text clipped - 17 lines] > moment. It's still being accelerated downward > by gravity. Wrong, at the 0 velocity it does have 0 downward force. And it also has a 0 acceleration wrt the ground if thrown exactally "straight up". Poor Greg, he is trying to give an acceleration that does not exist between the ground and the mass when it "is not moving wrt the ground for that brief moment. You truly should try to think some day Greg. :) >> and then the force increases from then on. > > No, the force stays the same. The velocity increases > in the downward direction. The brief moment it stops and reverses, it has no velocity Greg. Why are you so silly? >> Because of the energy differences above and below. >> above has the higher energy (more freedom of motion) [quoted text clipped - 3 lines] > that might be, has nothing to do with it. It's strictly > gravitational potential in the Earth's gravitational field. Poor Greg. he can't grasp that the potential differences cause the freedom of motion differences and the dang falling itself.. But of course he would rather have it be caused by some stupid a.s force called "spacetime" ROFLOL SignatureJames M Driscoll Jr Spaceman >>>> Uncle Al, Aren't you the idiot now? The Equivalence principle is >>>> exactly what I was saying in my post. It's just so obviously true [quoted text clipped - 21 lines] > Wrong, > at the 0 velocity it does have 0 downward force. Of course it does. Do you think gravity turns off because a body has zero downward velocity? How about a body in orbit? > And it also has a 0 acceleration wrt the ground > if thrown exactally "straight up". No, it has an acceleration of 1g, directed downwards. > Poor Greg, he is trying to give an acceleration > that does not exist between the ground and the mass > when it "is not moving wrt the ground for that brief > moment. > You truly should try to think some day Greg. You should take some physics courses someday, perhaps along with some differential calculus. >>> and then the force increases from then on. >> [quoted text clipped - 4 lines] > velocity Greg. > Why are you so silly? Why can't you understand that zero is a perfectly good value for a velocity? Since velocity is relative, one person's zero may be another person's 100. Just because something has zero velocity (even briefly) for some observer, it does not mean that there is zero force. Take for example a large mass M at rest sitting on a smooth surface. A force F is applied at time=0. At time=0 the velocity is zero, but the force is F. The body has an acceleration of A = F/M. At time 0+ (a very, very short time after 0), the object will have some nonzero velocity. It will still have the force F applied, and still experience acceleration A = F/M. >>> Because of the energy differences above and below. >>> above has the higher energy (more freedom of motion) [quoted text clipped - 7 lines] > cause the freedom of motion differences and the dang falling > itself.. Define "feedom of motion". Give an equation. > But of course he would rather have it be caused by some > stupid a.s force called "spacetime" So, you think "spacetime" is a force too? Is everything a force with you? >>>>> Uncle Al, Aren't you the idiot now? The Equivalence principle is >>>>> exactly what I was saying in my post. It's just so obviously true [quoted text clipped - 25 lines] > because a body has zero downward velocity? How > about a body in orbit? What the hell are you saying, I did not say gravity turns off, it simply gets "balanced" at that point of 0 velocity. (that tiny moment that the mass is (at rest) with the ground but just not touching it.) >> And it also has a 0 acceleration wrt the ground >> if thrown exactally "straight up". > > No, it has an acceleration of 1g, directed downwards. Are you freaking brainddead? 0 velocity, 0 acceleration (that brief moment before it changes direction) how do you get 1 g from those 2 zeros? Sheesh! >> Poor Greg, he is trying to give an acceleration >> that does not exist between the ground and the mass [quoted text clipped - 4 lines] > You should take some physics courses someday, > perhaps along with some differential calculus. Insultation physics.. nice diversion tactic as usual. :) >> The brief moment it stops and reverses, it has no >> velocity Greg. [quoted text clipped - 4 lines] > relative, one person's zero may be another person's > 100. I did not mention the other stuff yet. but then again.. you once said acceleration is absolute. now you change your mind? So you admit no such thing as "absolute" acceleration now? LOL > Just because something has zero velocity (even > briefly) for some observer, it does not mean that > there is zero force. It does mean 0 force wrt the ground below it that is "doing the pulling". :) > Take for example a large mass M at rest sitting on > a smooth surface. A force F is applied at time=0. [quoted text clipped - 4 lines] > have the force F applied, and still experience > acceleration A = F/M. At time 0 the Force is 0 still, you need the time to increase to >0 to become a force at all just as you need the motion wrt Earth no not be 0 to have a motion at all wrt Earth. Poor Greg. He is all mixed up now.. He will try to twist his way out and come up with some crazy stuff like acceleration is absolute. You just don't understand why.. and ...yadda yadda and spacetime curvature proves the math so bla blah blah and GPS blah! LOL >> Poor Greg. he can't grasp that the potential differences >> cause the freedom of motion differences and the dang falling >> itself.. > > Define "feedom of motion". Give an equation. Space Equation for freedom? hmm I will try but usually you don't need equations to define stuff. maybe ..... Freedom = x,y,or z + >0 If not.. I don't care because at least I know what freedom of motion is without the math. :) >> But of course he would rather have it be caused by some >> stupid a.s force called "spacetime" > > So, you think "spacetime" is a force too? Is everything > a force with you? spacetime is your supposed physical cause for gravity.. You are the one that thinks it is a force.. not I. LOL SignatureJames M Driscoll Jr Spaceman >>>>>> Uncle Al, Aren't you the idiot now? The Equivalence principle is >>>>>> exactly what I was saying in my post. It's just so obviously [quoted text clipped - 30 lines] > (that tiny moment that the mass is (at rest) with the ground > but just not touching it.) But it doesn't. It is still accelerating downwards at 1g. Acceleration is not velocity. It's the rate of change of velocity. At the moment that the body is instantaneously at rest in its path, its velocity is *still* changing, passing from a + (unpward) value to a - (downward) value. >>> And it also has a 0 acceleration wrt the ground >>> if thrown exactally "straight up". [quoted text clipped - 5 lines] > it changes direction) how do you get 1 g from those > 2 zeros? Simple. There aren't two zeros. The acceleration is still there. You really don't understand Newtonian mechnanics if you think that any particular velocity value specifies a corresponding acceleration value. >>> Poor Greg, he is trying to give an acceleration >>> that does not exist between the ground and the mass [quoted text clipped - 80 lines] > You are the one that thinks it is a force.. not I. > LOL >> What the hell are you saying, I did not say gravity turns >> off, it simply gets "balanced" at that point of 0 velocity. [quoted text clipped - 3 lines] > But it doesn't. It is still accelerating downwards > at 1g. When it is at the point it is basically motionless for a tiny moment. It is not accelerating downwards or forwards anymore at all Greg. Are you really that ignorant Do you really think you can just "skip" the zeros? LOL SignatureJames M Driscoll Jr Spaceman > Acceleration is not velocity. It's the rate > of change of velocity. At the moment that the body > is instantaneously at rest in its path, its velocity > is *still* changing, passing from a + (unpward) > value to a - (downward) value. And at one point in time, you can not call it changing rate at all because it had to "stop" to reverse direction at all and then change rate again. Sheesh you are priceless. The acceleration had to "STOP" to completely reverse direction. You truly are yet another smartest stupid person. :) > Simple. There aren't two zeros. The acceleration is > still there. You really don't understand Newtonian > mechnanics if you think that any particular velocity > value specifies a corresponding acceleration value. Sorry, You just refuse to get it. What does "stop" mean Greg? Do you think you can change direction to complete reverse without stopping forward motion first? You are lost man! SignatureJames M Driscoll Jr Spaceman >>> What the hell are you saying, I did not say gravity turns >>> off, it simply gets "balanced" at that point of 0 velocity. [quoted text clipped - 8 lines] > It is not accelerating downwards or forwards anymore > at all Greg. Yes it is. Can't you distinguish velocity from acceleration? > Are you really that ignorant > Do you really think you can just "skip" the zeros? Velocity is relative. Change your observers frame of reference and the zeros go away. But the acceleration remains. >> Acceleration is not velocity. It's the rate >> of change of velocity. At the moment that the body [quoted text clipped - 9 lines] > reverse direction. > You truly are yet another smartest stupid person. So, we conclude that James never took high school physics. James has the naive kindergarten understanding of acceleration and velocity wherein if the velocity is instantaneously zero in some frame of reference, then all other values related to motion (such as acceleration) must also be zero. >> Simple. There aren't two zeros. The acceleration is >> still there. You really don't understand Newtonian [quoted text clipped - 4 lines] > You just refuse to get it. > What does "stop" mean Greg? It means no motion with respect to some arbitrary frame of reference. Note that "stopped" in one frame of reference does not imply stopped in others. > Do you think you can change direction to complete > reverse without stopping forward motion first? Of course not. But acceleration is not velocity, it's the rate of change of velocity. >>>> What the hell are you saying, I did not say gravity turns >>>> off, it simply gets "balanced" at that point of 0 velocity. [quoted text clipped - 11 lines] > Yes it is. Can't you distinguish velocity from > acceleration? I can, you can't. You think you can have a 0 velocity and still have an acceleration apparently you don't even know how to use an acceleration equation. Show me how you can place a 0 as the velocity and still get an acceleration. You are a freakin moron! Brainwashed beyond help LOL > Velocity is relative. Change your observers frame of > reference and the zeros go away. But the acceleration > remains. LOL Yet again, you need to frame jump, yet if I try to do such you say it is wrong! ROFLOL > So, we conclude that James never took high school physics. > James has the naive kindergarten understanding of > acceleration and velocity wherein if the velocity is > instantaneously zero in some frame of reference, then > all other values related to motion (such as acceleration) > must also be zero. Poor Greg, back to the paragraphs worth of insults so he can "never be wrong". Use relativity only when it supports relativity but ignore relative motion if it creates a paradox. Greg. That is rule number one huh? LOL > It means no motion with respect to some arbitrary frame > of reference. Note that "stopped" in one frame of > reference does not imply stopped in others. Of course, frame jumping is allowed only when it "supports" relativity. LOL >> Do you think you can change direction to complete >> reverse without stopping forward motion first? > > Of course not. But acceleration is not velocity, it's > the rate of change of velocity. And the rate of change at 0 velocity is 0 change. Again, please show an acceleration that uses a 0 velocity. LOL You freakin rubber ruler goof! LOL SignatureJames M Driscoll Jr Spaceman >>>>> What the hell are you saying, I did not say gravity turns >>>>> off, it simply gets "balanced" at that point of 0 velocity. [quoted text clipped - 13 lines] > > I can, you can't. Clearly a false statement. > You think you can have a 0 velocity and still have an acceleration > apparently you don't even know how to use an acceleration > equation. James is stuck in kindergarten mode again. > Show me how you can place a 0 as the velocity and still get > an acceleration. Let acceleration be A = -10 m/s^2 (that is, a deceleration just like gravity on an object thrown upwards). Let initial upward velocity be V0 = +100 m/sec. V(t) = V0 + A*t Compute a table of velocity values with respect to time: Time Acceleration Velocity (seconds) (m/sec^2) (m/sec) 0 -10 +100 Object launched upwards 1 -10 90 2 -10 80 3 -10 70 4 -10 60 5 -10 50 6 -10 40 7 -10 30 8 -10 20 9 -10 10 10 -10 0 Object momentarily at rest 11 -10 -10 12 -10 -20 13 -10 -30 14 -10 -40 15 -10 -50 etc. > You are a freakin moron! You can't do physics. All you can do is resort to insults, the last refuge in a lost argument. >> Velocity is relative. Change your observers frame of >> reference and the zeros go away. But the acceleration [quoted text clipped - 3 lines] > Yet again, you need to frame jump, yet if I try > to do such you say it is wrong! Moving from frame to frame to frame is fine as long as you transform your variables accordingly. It's *not* okay to take a value in one frame (like velocity) and hop to another frame using that same numerical value. Do you *still* not understand and recognize frame jumping when you see it? >> So, we conclude that James never took high school physics. >> James has the naive kindergarten understanding of [quoted text clipped - 6 lines] > back to the paragraphs worth of insults so he > can "never be wrong". James needs only simple correct declarative statements to be right. > Use relativity only when it supports relativity > but ignore relative motion if it creates a paradox. Note: James thinks we've been discussing Relativity while this discussion has been purely Galilean and Newtonian. He invokes "Relativity" any time he thinks he's only wrong because some "Relativist" trick is being pulled on him, when the reality is, he's just wrong. > Greg. > That is rule number one huh? [quoted text clipped - 6 lines] > Of course, frame jumping is allowed only when it > "supports" relativity. See? James thinks Special Relativity is involved here. >>> Do you think you can change direction to complete >>> reverse without stopping forward motion first? [quoted text clipped - 3 lines] > > And the rate of change at 0 velocity is 0 change. No, it is not. That is very basic physics, James. Go over the train example again. At the time that the relative speeds of the train was zero, did the acceletation of train B suddenly turn off? > Again, please show an acceleration that uses a 0 velocity. See above. >> Show me how you can place a 0 as the velocity and still get >> an acceleration. > > Let acceleration be A = -10 m/s^2 (that is, a deceleration > just like gravity on an object thrown upwards). Let initial > upward velocity be V0 = +100 m/sec. So now you use speed instead of velocity. Nice twist Greg! too bad you need a direction for that speed so it can be relative to anything to prove it is a speed at all. LOL > V(t) = V0 + A*t (t) = 0 HA HA HA HA HA HA A = 0 you have zeros and just love to ignore them! LOL > Compute a table of velocity values with respect to time: > > Time Acceleration Velocity > (seconds) (m/sec^2) (m/sec) > 0 -10 +100 Object launched upwards What is it's forward acceleration rate? LOL > 1 -10 90 Ohh so it is constantly deccellerating and never reaches a 0 decceleration rate to reverse direction later on? LOL > 2 -10 80 > 3 -10 70 [quoted text clipped - 4 lines] > 8 -10 20 > 9 -10 10 Bingo! Poor Greg. He thinks acceleration is constant when something is "slowing down" and reversing speed. ROFLOL SignatureJames M Driscoll Jr Spaceman >>> Show me how you can place a 0 as the velocity and still get >>> an acceleration. [quoted text clipped - 7 lines] > too bad you need a direction for that speed so > it can be relative to anything to prove it is a speed at all. What?!? What are you nattering on about now? If you have an objection to the proposed model, spell it out and suggest a better one. >> V(t) = V0 + A*t > > (t) = 0 > HA HA HA HA HA HA You object to the use of a stopwatch to time the motion? > A = 0 A = -10 m/sec^2. It is not zero. So you are making things up again (i.e. lying). > you have zeros and just love to ignore them! Zeros ahead James. Fasten your seatbelt. >> Compute a table of velocity values with respect to time: >> [quoted text clipped - 3 lines] > > What is it's forward acceleration rate? The motion is followed from the time it is launched (t = 0 by the stopwatch). How it got to its launch velocity is not important. If you want to specify a method, path, and acceleration leading up to the launch you are free to do so. It will not affect subsequent motion. >> 1 -10 90 > > Ohh so it is constantly deccellerating and > never reaches a 0 decceleration rate > to reverse direction later on? Right. You're catching on. > LOL Or maybe not. >> 2 -10 80 >> 3 -10 70 [quoted text clipped - 9 lines] > He thinks acceleration is constant > when something is "slowing down" and reversing speed. Tell us James, what value you see in the acceleration column all the way down. It changing? No, it is not. The velocity is changing, but the acceleration is not. > A = -10 m/sec^2. It is not zero. So you are making things > up again (i.e. lying). A "constant acceleration" that slows down and reverses direction! ROFLOL! > Tell us James, what value you see in the acceleration column > all the way down. It changing? No, it is not. The velocity > is changing, but the acceleration is not. The "not changing" is your problem Greg. a not changing "acceleration" can not "reverse" direction. Stupid a.s textbook head. LOL How does something moving at direction "negative" change to positive without stopping? How does something moving positive direction change to a negative direction without stopping. You are very ignorant of the "stopping fact" that must occur! LOL SignatureJames M Driscoll Jr Spaceman >> A = -10 m/sec^2. It is not zero. So you are making things >> up again (i.e. lying). > > A "constant acceleration" that slows down and reverses > direction! The acceleration is not changing direction, it is constant in the chosen frame of reference. It is the velocity that reverses direction. >> Tell us James, what value you see in the acceleration column >> all the way down. It changing? No, it is not. The velocity >> is changing, but the acceleration is not. > > The "not changing" is your problem Greg. > a not changing "acceleration" can not "reverse" direction. Correct. The acceleration does not reverse direction. The velocity does. > Stupid a.s textbook head. Oooh, I'm sooo hurt. > LOL > How does something moving at direction "negative" > change to positive without stopping? If you allow non-linear motion, it can move in a circle, for example. > How does something moving positive direction > change to a negative direction without stopping. By moving in a non-linear trajectory. Otherwise it does come to a stop for a single instant. What's the problem? > You are very ignorant of the "stopping fact" > that must occur! Hardly. I never said that the velocity doesn't achieve a zero magnitude. I said that the acceleration is constant. >>> A = -10 m/sec^2. It is not zero. So you are making things >>> up again (i.e. lying). [quoted text clipped - 15 lines] > Correct. The acceleration does not reverse direction. > The velocity does. Ahh, So you think acceleration is never a deceleration and a change in direction does not chnage something from decceleration to acceleration. Stuck on that number line and forgetting that even if you move negatively, you are moving that negative direction in a positive motion. LOL You should have never learn about "velocity" Greg. It has you confused about what direction actually means. LOL > If you allow non-linear motion, it can move in a > circle, for example. Aha! Now you wish to jump outside the box again! Funny how you can't do that unless you need to! LOL > Hardly. I never said that the velocity doesn't achieve > a zero magnitude. I said that the acceleration is > constant. As I said. Show an acceleration with a 0 velocity and 0 speed. You can't do it.. Try and think for once. LOL SignatureJames M Driscoll Jr Spaceman >>>> A = -10 m/sec^2. It is not zero. So you are making things >>>> up again (i.e. lying). [quoted text clipped - 23 lines] > that even if you move negatively, you are moving that negative > direction in a positive motion. You pick your frame of reference and coordinate system and stick with it. You don't change it in the middle of the analysis. Acceleration and Decceleration are terms applied depending upon one's point of view. It's a leftover terminolgy from its mundane usage. In physics it is better to stick with the one term, acceleration, and allow it to take on whatever values are required, positive or negative. > You should have never learn about "velocity" Greg. > It has you confused about what direction > actually means. The only confusion that seems to be occurring here is your's because you don't want to choose a coordinate system and stick to it. >> If you allow non-linear motion, it can move in a >> circle, for example. > > Aha! > Now you wish to jump outside the box again! > Funny how you can't do that unless you need to! I'm simply pointing out an example that satisfies your query. I'm not suggesting that this is the case under consideration. If you don't want an answer, why ask the question? >> Hardly. I never said that the velocity doesn't achieve >> a zero magnitude. I said that the acceleration is >> constant. > > As I said. > Show an acceleration with a 0 velocity and 0 speed. V = a*t At t=0, v=0. > You can't do it.. Sorry, I just did it. I also did it with the train example when the trains were matched in speed. Their relative velocites was zero, while train B was still accelerating. > You pick your frame of reference and coordinate system > and stick with it. You don't change it in the middle of > the analysis. There we go again! Now you say I can't frame jump but you could earlier. LOL Nevermind Greg.. You are not even attempting to think about your ignorance of relativity to support your relativity. LOL SignatureJames M Driscoll Jr Spaceman >> You pick your frame of reference and coordinate system >> and stick with it. You don't change it in the middle of >> the analysis. > > There we go again! > Now you say I can't frame jump but you could earlier. I don't frame jump, I transform the observed quantities appropriately when I move from frame to frame. And I specifically call out the transformations so there is no confusion. James, as I've told you in the past, you can frame jump if you want to, provided you are fastidious about keeping track of the required adjustments to values due to the change in frames. When you frame jump without paying attention to the details, I'll call you on it. > Nevermind Greg.. > You are not even attempting to think about your > ignorance of relativity to support your relativity. Hey, if you know something I don't please share so we can all benefit. > I don't frame jump, I transform the observed quantities > appropriately when I move from frame to frame. And I > specifically call out the transformations so there is > no confusion. What a bunch of bullshit. Frame jumping is frame jumping no matter what you "bring with you". Sheesh! Get a freakin clue some year Greg. You truly have not even one clue right now. SignatureJames M Driscoll Jr Spaceman >> I don't frame jump, I transform the observed quantities >> appropriately when I move from frame to frame. And I [quoted text clipped - 4 lines] > Frame jumping is frame jumping no matter > what you "bring with you". James doesn't understand frame jumping. Hey James, let me give you a simple example that you should be able to handle. Suppose person A is six feet tall, and is standing at the top of a cliff that is 100 feet tall. Person B is standing on the ground at the foot of the cliff. In person B's frame of reference is the top of person A's head six feet above the ground where B is standing or 106 feet? If you said 6 feet you would be frame jumping. If you said 106 feet you would be performing a valid frame transformation. > James doesn't understand frame jumping. Greg doesn't understand anything. Nice work Greg. LOL > "Spacedoutman" <spaceman@yourclockmalfunctioned.duh> wrote in message > news:DpadnVbWGsUC0-nVnZ2dnUVZ_oninZ2d@comcast.com [...] >>What the hell are you saying, I did not say gravity turns >>off, it simply gets "balanced" at that point of 0 velocity. >>(that tiny moment that the mass is (at rest) with the ground >>but just not touching it.) > But it doesn't. It is still accelerating downwards > at 1g. Acceleration is not velocity. It's the rate > of change of velocity. At the moment that the body > is instantaneously at rest in its path, its velocity > is *still* changing, passing from a + (unpward) > value to a - (downward) value. The moment you're talking about clearly describes one of the many problems Mitch has understanding what's actually happening. Untutored people (to borrow an expression from Uncle Al) tend to get lost in the words. I prefer the description "the great unwashed." They tend to have muddy minds, a condition that may or may not be correctable. If one looks at a zero width timeslice of something in motion, in that model absolutely nothing is happening. But of course that's only a model. There is no stopping time despite the fact that in science we can deal with such models and do so often. The model is not the reality. Just because James Driscoll can imagine having sex with some long dead beauty queen (to say nothing of imagining himself with a live one) has nothing to do with the realities of the actual situation. And in Driscoll's case there's nothing to be learned anyway. In science we study models in order to understand the reality, often by taking very narrow (for all practical purposes, zero width) timeslices, and then looking at how whatever is being studied behaves in sequential, or sequentially spaced out, images. One can only actually observe the effects by putting together what happens in a series of those momentary images. None of the instantaneous images by itself is meaningful in any context despite the fact we can discuss the moment in the context of what came before and after. The unwashed just don't get it no matter how many times and in how many different ways this is explained to them. <snipped the pat on the back church goers babble> > If one looks at a zero width timeslice of something in > motion, in that model absolutely nothing is happening. [quoted text clipped - 8 lines] > situation. And in Driscoll's case there's nothing to > be learned anyway. Ahh. So you also think you can just "skip" the zeros and pretend they did not occur! LOL SignatureJames M Driscoll Jr Spaceman >>> The brief moment it stops and reverses, it has no >>> velocity Greg. [quoted text clipped - 9 lines] > now you change your mind? > So you admit no such thing as "absolute" acceleration now? Nope. Any observer in any inertial frame will see the acceleration. >> Just because something has zero velocity (even >> briefly) for some observer, it does not mean that >> there is zero force. > > It does mean 0 force wrt the ground below it that is > "doing the pulling". No. Gravity does not turn off. The 1g acceleration remains. Try a simple linear example, James. Two trains are moving in the same direction along parallel tracks. Train A is moving at a constant speed of 30 km/hr. Train B is currently moving at 20 km/hr so the relative velocity of train B with respect to train A is -10 km/hr (it is going slower and thus falling behind train A). Train B begins to accelerate at fixed, contant rate of acceleration. At some time t the relative speeds of the trains is zero (train B has matched speeds with train A) but continues to accelerate, passing train A. Now, do you think the acceleration of train B stopped in the instant that its relative speed with respect to train A was zero? Would an observer on the banks of the tracks see the acceleration suddenly turn off and on again when the trains matched speeds? How about passengers on train B? Will they feel a sudden jerk when the two trains match speeds, signalling the acceleration changing from some positive value to zero, and back to some positive value? >> Take for example a large mass M at rest sitting on >> a smooth surface. A force F is applied at time=0. [quoted text clipped - 9 lines] > as you need the motion wrt Earth no not be 0 > to have a motion at all wrt Earth. No. I specified that the force F was applied at time t=0. Not at some time after t=0, nor at some time before t=0. At t=0 exactly. > Poor Greg. > He is all mixed up now.. [quoted text clipped - 3 lines] > and spacetime curvature proves the math so bla blah blah > and GPS blah! James is ranting incoherently again. Must be time for his meds. >>> Poor Greg. he can't grasp that the potential differences >>> cause the freedom of motion differences and the dang falling [quoted text clipped - 9 lines] > maybe ..... > Freedom = x,y,or z + >0 Gibberish. Suppose I plug some random set of numbers into that for z,y, and z. What would it tell me? Suppose I plugged another random set of numbers into that, what would it tell me and what would it tell me with respect to the last set of numbers? > If not.. I don't care because at least I know > what freedom of motion is without the math. If you don't have an equation, you don't have anything in science. A "feeling" is not a definition. It's resorting to mysticism and magic. >>> But of course he would rather have it be caused by some >>> stupid a.s force called "spacetime" [quoted text clipped - 4 lines] > spacetime is your supposed physical cause for gravity.. > You are the one that thinks it is a force.. not I. James doesn't understand the difference between a thing and its source, a cause and an affect. >>>> The brief moment it stops and reverses, it has no >>>> velocity Greg. [quoted text clipped - 22 lines] > No. Gravity does not turn off. The 1g acceleration > remains. So again you say you were wrong about acceleration being absolute but just refuse to say it kinda like Fonzie. LOL > Try a simple linear example, James. Two trains are > moving in the same direction along parallel tracks. [quoted text clipped - 8 lines] > train A) but continues to accelerate, passing train > A So now when needed you bring the "outside the box" because you need to. but sadly, the two trains in our object tossed straight up and falling backdown are not staying parrallel and are not traveling at different velocities wrt to each other. Both "trains" always have the same velocity while inside your little box. so... What is moving towards the other one, The Earth or the ball that is thrown straight up? Isn't it relative or do you get to throw relativity away to prove relativity again? LOL SignatureJames M Driscoll Jr Spaceman > Now, do you think the acceleration of train B stopped > in the instant that its relative speed with respect to [quoted text clipped - 73 lines] > James doesn't understand the difference between a thing > and its source, a cause and an affect. >>>>> The brief moment it stops and reverses, it has no >>>>> velocity Greg. [quoted text clipped - 26 lines] > being absolute but just refuse to say it kinda like > Fonzie. James' reading comprehension problem noted (again). What part of "The 1g acceleration remains" does James think implies that it disappears? >> Try a simple linear example, James. Two trains are >> moving in the same direction along parallel tracks. [quoted text clipped - 11 lines] > So now when needed you bring the "outside the box" > because you need to. What box is that James? Could it be you're just trying to avoid facing your errors? > but sadly, the two trains in our object tossed straight > up and falling backdown are not staying parrallel and > are not traveling at different velocities wrt to each other. Are you saying that the object and the Earth are not moving at different velocities when you toss the object? Are you saying that the object tossed straight up is not moving in a straight line with respect to the Earth? > Both "trains" always have the same velocity while > inside your little box. What makes you think that? I specifically gave the trains different velocities, and one of them an acceleration, too. More reading comprehension problems, James? > so... > What is moving towards the other one, > The Earth or the ball that is thrown straight up? Choose either as a point of reference. The other will be moving with respect to it. > Isn't it relative or do you get to throw relativity > away to prove relativity again? Of course it's relative. But what has this got to do with the issue? Methinks James is ducking and diving for cover again. > James' reading comprehension problem noted (again). > What part of "The 1g acceleration remains" does > James think implies that it disappears? 1 G acceleration with a 0 velocity? You truly love to be totally ignorant of your own math church when needed. ROFLOL > Are you saying that the object and the Earth are not > moving at different velocities when you toss the > object? Are you saying that the object tossed > straight up is not moving in a straight line with > respect to the Earth? According to each other, both objects always have the same velocity and acceleration wrt each other if they are moving directly towards or directly away from each other. Poor Greg, he really does not understand relativity. LOL >> Both "trains" always have the same velocity while >> inside your little box. [quoted text clipped - 3 lines] > acceleration, too. More reading comprehension > problems, James? You gave the trains different velocities that the ball and the Earth do not have wrt each other. :) So sad you will twist until you snap won't you? LOL > Choose either as a point of reference. The other > will be moving with respect to it. Earth says the ball is moving. The ball says the Earth is moving. Both come up with the same velocity and acceleration wrt each other all the time! LOL Greg is so lost in relativity he forgets how relativity works. ROFLOL SignatureJames M Driscoll Jr Spaceman >> James' reading comprehension problem noted (again). >> What part of "The 1g acceleration remains" does [quoted text clipped - 3 lines] > You truly love to be totally ignorant of > your own math church when needed. James, who cannot do math, is proclaiming what the math says. That is, argument from ignorance. James cannot fathom the fact that the math says that the acceeleration can be constant (non zero) the whole time, while the velocity can take on any value including zero from arbitrary frames of reference. V(t) = V0 + A*t >> Are you saying that the object and the Earth are not >> moving at different velocities when you toss the [quoted text clipped - 5 lines] > velocity and acceleration wrt each other if they are moving > directly towards or directly away from each other. That is true, with an appropriate change of sign. But that is not what I was asking. You implied that the object tossed in the air was not changing velocity with respect to the Earth frame of reference, and that it was not following a straight line path. >>> Both "trains" always have the same velocity while >>> inside your little box. [quoted text clipped - 6 lines] > You gave the trains different velocities that the ball > and the Earth do not have wrt each other. So? Do you think specific numbers make a difference to a general principle? The train example was chosen to simplify the arrangement for your benefit. It added an external frame of reference (from trackside) in which the motion of both trains is always positive and non-zero. The relative velocities of the trains as viewed from aboard the constant velocity train would be just like the vertically tossed object as viewed from the ground. Can't you see that? > :) > So sad you will twist until you snap won't you? James thinks his inability to comprehend constitutes deception on every body else's part. >> Choose either as a point of reference. The other >> will be moving with respect to it. > > Earth says the ball is moving. > The ball says the Earth is moving. Correct so far. > Both come up with the same velocity and acceleration > wrt each other all the time! Not quite; the magnitudes are the same but the signs are reversed (if you're keeping the axes of your frame coordinates oriented in the same directions). > LOL > Greg is so lost in relativity he forgets how relativity > works. James *still* thinks that Special Relativity is involved here. Amazing. >>> James' reading comprehension problem noted (again). >>> What part of "The 1g acceleration remains" does [quoted text clipped - 11 lines] > any value including zero from arbitrary frames > of reference. A decceleration even at a constant speed ends up being a stop at one point and when the "stop" occurs. the acceleration rate no longer is deccelerating. and it will then start to "accelerate" in the opposite direction. Again, Greg gives an absolute acceleration only when it it supports relativity but not when it makes fun of relativity. LOL > But that is not what I was asking. You implied that > the object tossed in the air was not changing velocity > with respect to the Earth frame of reference, and that > it was not following a straight line path. I did not say it was not following a straight line path. I specifically said it is tossed straight up and comes straight down. Your twisting "as usual" is noted. SignatureJames M Driscoll Jr Spaceman >>>> James' reading comprehension problem noted (again). >>>> What part of "The 1g acceleration remains" does [quoted text clipped - 16 lines] > and when the "stop" occurs. > the acceleration rate no longer is deccelerating. The acceleration is *constant*. It's the velocity that's changing. > and it will then start to "accelerate" in the opposite direction. The acceleration never changes, it's the velocity that's changing. > Again, > Greg gives an absolute acceleration only when it it supports > relativity but not when it makes fun of relativity. James should back up his assertions with proof. He should provide an example of where I claimed that acceleration is changed versus another where I said it is not changing for the same case. Otherwise I say James is lying. >> But that is not what I was asking. You implied that >> the object tossed in the air was not changing velocity [quoted text clipped - 4 lines] > I specifically said it is tossed straight up and comes > straight down. Then why did you subsequently imply that that it wasn't? > Your twisting "as usual" is noted. You're claiming another is twisting when you made the error is noted. >>>>> James' reading comprehension problem noted (again). >>>>> What part of "The 1g acceleration remains" does [quoted text clipped - 19 lines] > The acceleration is *constant*. It's the velocity > that's changing. You really don't want to think about that huh? Once the velocity is 0, how do you have acceleration at all? A 0 velocity or speed creates a 0 acceleration. Sheesh Greg. I can see you will never even try to get it so we might as well just forget it. :) Forget it Greg. I know you are always right and never wrong. LOL SignatureJames M Driscoll Jr Spaceman >>>>>> James' reading comprehension problem noted (again). >>>>>> What part of "The 1g acceleration remains" does [quoted text clipped - 23 lines] > Once the velocity is 0, how do you have > acceleration at all? The acceleration is not dependent on the velocity in the way you imagine it to be. The velocity passes through zero, it does not hang about there. The acceleration is the rate of change of velocity. > A 0 velocity or speed creates a 0 acceleration. No, that's a kindergarten level thinking. James needs to learn about and do some thinking upon rates of change of a value versus the value itself. > Sheesh Greg. > I can see you will never even try to get it so > we might as well just forget it. You certainly may opt not to understand this simple bit of physics, but it will not bode well for your understanding of more complex things built upon this basic knowledge. > An object subject to a gravitational field must accellerate. That is > is must constantly increase speed. That's interesting. When I chuck a lemon into the air vertically upward, it seems to DECREASE speed under the influence of the gravitational field. In fact, when I chuck a lemon up to Ralph in the third floor window, it seems to be decreasing speed the whole trip. Hmmm.... <scratching head> |
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