So, you're basically saying that "it's just math, stupid!" (okay, okay, that's a colloquialism and you didn't actually call me or Johannes stupid; hehe) and doesn't describe anything real. Loveli!

So, what good is something that doesn't describe a real thing? Or it does describe some realtionship between real things, but we don't know how to communicate that relationships in every-day language?

However, most of what you've said CAN be expressed in real-world understandable language. So, why is it that some things can and some things can't?

Speed is distance divided by time. IE, if you move 10 meters in 2 seconds, it's equivalent to moving 5 meters in 1 second, or 2.5 meters in 0.5 seconds. Real language works fine to understand it.

Velocity is the same as above, but includes directionality. IE, something moves 10 meters in 2 seconds in the direction west. Again, real language works FINE.

Momentum is a bit trickier, since now we're adding mass into the equation an nobody really seems to be able to communicate what "mass" is. However, momentum is essentially saying we know 4 things: Mass, Velocity (distance/time, direction). Though what it means to multiply a "mass" and a distance seems very unintuitive. If for no other reason than "mass" seems to be poorly defined in terms of a physical process. I mean, what constitutes "mass?" We seem to be unable to define that very well, so far. Or more aptly, what defines the "mass" of 1 kilogram? Our definition seem slippery, since the original definition was circular, and the new definition seems to have gotten "lighter" over the last 100 years (according to Wikipedia). Now, if we had a better definition of what "mass" is (including how it's structured and the actual physical processes involved), this whole issue might be resolved, assuming the structures can be talked about by rational humans in natural language.

Acceleration/deceleration, is simple in real laguage: It's the change in velocity over time. IE, how much speed/direction is gained or lost over a specific interval. So, if no speed or direction has been gained or lost, velocity is constant and acceleration/deceleration is zero. If something was moving at 9.8 m/s and increases to 10.8 m/s over the course of 1 second, then we have an acceleration over that second of 1 m/s. Real language works fine.

Now then, a force. This is, according to the math: Mass times acceleration. Or it's momentum over time, depending on how you arrange the equation. But it's saying that we can calculate the force if we know mass, and we know acceleration, or if we know momentum and time. Though the definition of "mass" is still an issue in terms of real language.

My point being that real language can be used perfectly fine so long as we have a good definition of the terms involved. However, multiplying a mass times a distance still seems weird and counterintuitive. Since mass and distance aren't like terms. Unless there's an underlying definition of "mass" that has to do with distance. That's at least part of why I asked the e=m(c^2) question to begin with, to understand what "mass" is, since my understanding of "mass" was less than complete. Now it seems like the general definition of "mass" seems incomplete, if we can't define it in terms of understandabel concepts in real language. If it doesn't describe a real, understandable thing, then it's nothing more than a mathematical construct with no real meaning and shouldn't be given the weight it is (no pun intended, but I'll take it anyway). But mass seems to be intergral to just about every calculation we do on celestial objects, objects here on Earth, so it's my thought that we should try to have an understanding of what "mass" actually is. Is it a REAL thing, or an IMAGINARY mathematical thing?

I mean we say that mass can be converted into energy and vice versa, and in labs it seems like we try to manipulate mass and energy all the time. So, it seems to be a REAL thing. So, why can't we explain it in real-world terms that make sense just like everything else in the equations OTHER THAN mass make sense?

Wikipedia:
"In Newtonian mechanics, there are three types of mass or properties called mass:

* Inertial mass is a measure of an object's resistance to changing its state of motion when a force is applied. An object with small inertial mass changes its motion more readily, and an object with large inertial mass does so less readily.
* Passive gravitational mass is a measure of the strength of an object's interaction with the gravitational field. Within the same gravitational field, an object with a smaller passive gravitational mass experiences a smaller force than an object with a larger passive gravitational mass. (This force is called the weight of the object. In informal usage, the word "weight" is often used synonymously with "mass", because the strength of the gravitational field is roughly constant everywhere on the surface of the Earth. In physics, the two terms are distinct: an object will have a larger weight if it is placed in a stronger gravitational field, but its passive gravitational mass remains unchanged.)
* Active gravitational mass is a measure of the strength of the gravitational field due to a particular object. For example, the gravitational field that one experiences on the Moon is weaker than that of the Earth because the Moon has less active gravitational mass.

Although inertial mass, passive gravitational mass and active gravitational mass are conceptually distinct, no experiment has ever unambiguously demonstrated any difference between them. This empirical observation leads to the equivalence principle of general relativity. The weak form of the equivalence principle states that this correspondence between inertial and gravitational masses is not accidental, and that no experiment will ever detect a difference between them."

If we consider mass to be the resistance to acceleration, does that make any more sense in the equations that simply a "name" (mass)?

Well, momentum would be "resistance to acceleration" multiplied by velocity (direction, distance/time) times.
Force would be "mass" mulitplied by acceleration (change in velocity).

Force is "resistance to acceleration" times "acceleration". Heh, that's funny. What the hell does that mean? It's like multiplying opposites.

Okay, so acceleration is positive change in velocity. Decelration is negative change in velocity. (Velocity over time.)
Velocity is change in position. (Distance over time, with a directional component: up, down, left, right, N/E/S/W, etc.)
So acceleration is the change in the change of position over time. Or (Distance/Time)/Time, Or D/(T^2) (with T in seconds).

So, if acceleration is the change in velocity over time, what is the resistance to change in velocity over time? THAT, is the question of the hour, I suppose.

In laymen's terms, I suppose one could say (correct me if I'm wrong): how much directional energy can something absorb before it too starts moving in that direction (actually, that's not quite right, after having finished writing the rest, but I'll get to it in a second)? Consider it kind of like a pebble in a river. If the river is flowing slowly, it's probably imparting some small amount of kinetic energy to the pebble's atoms. Those atoms perhaps get jostled, thus jostling the next atoms, and so on in a tiny pressure wave through the pebble. And the pressure gets transmitted back out the other side of the pebble back into the fluid medium on the other side.

However, as the river picks up speed, it begins imparting more and more kinetic energy. Hmm, interesting.

One might say that it depends on how efficiently and quickly the pebble can re-transmit the kinetic energy through itself and back out the other side. If the pebble's atoms can transfer energy quickly enough, then the kinetic energy passes through the pebble, outh the other side and the pebble remains undisturbed, but as more end more energy is pumped into the system, the pebble's energy transfer system of jostling atoms gets overloaded, and suddenly it's being imparted more energy flux than its energy transfer mechanism can cope with, so its internal energy goes up. Rather, its velocity (which was 0 with respect to the river bed) increases in the direction it was imparted. One might say mathematically that it gained mass, and/or momentum as it was acted upon by a force and thusly imparted energy (a force beingthe imparting of energy at a specific rate). Since its ability to transmit energy was overloaded, it began to retain more and more energy, hence mass as well via translation of e=m(c^2) {? hmm, interesting in retrospect; it gains mass, but that would make it harder to push, thus a better outward energy transmitter in this model. If mass equals energy absorbtion/retransmission, then why would more energy in the system be equivalent to more ability to re-transmit energy? Odd. Perhaps it's a gradient, wherein higher energies allow for a higher outward push of energy; more pressure, if you will? Dunno. Will have to think more on this}, and began to gain velocity as well.

So, in this instance, one might consider "mass" to be the ability of a thing to resist acceleration by allowing energy to be transmitted through itself at a certain rate (or possibly re-radiated in other directions, not necessarily forward? Dunno.)... But when its ability to let that energy flow through it was maxed out, it began to retain that energy that it could not get rid of. The energy was imparted with an overall direction (the flow or velocity of the river), hence the pebble began to gain overall velocity in that direction. My guess would then be that if the pebble were carried to a wider, deeper, slower moving part of the channel, it would be able to more effectively eliminate internal energy again to come back to equilibrium (pressure wants to migrate or expand to areas of lower pressure), at which point, it might well reduce or eliminate its forward velocity/momentum, and again sink to the bottom of the channel in a fixed position (at rest).

So, again I may be wrong, but by talking it out, it seems like mass, is a thing's ability to transmit energy in a particular direction at a particular rate, while remaining immobile or at rest. It's only when the thing's ability to transmit energy at a particulr rate is overwhelmed that you get a build-up of energy, in which ever direction it was imparted... Once the force acting upon the object subsides, and it is able to re-radiate the energy, its mass and/or momentum and/or velocity may well return to whatever state it was at prior to acceleration. Or, if there's no drag to slow it down, inertia may keep it going. Though in that case, it probably wouldn't re-radiate much energy, but continue moving with the mass/momentum intact (as in acceleration in a vaccum).

Okay, there we go.

Mass might well simply be the ability to absorb, transmit and re-emit energy in such as way as to not affect its overall velocity. One might well say that absorbtion of energy equals emission of energy when it is at rest, such that there is no overall gain or loss of energy. It's only when it's unable to re-emit energy at a sufficent rate that the absorbtion of energy causes it to accelerate. Now, individual atoms obviously get accelerated, and knock each other around internally, but their individual absorbtion and emission rates would be much smaller than the whole of the object (pebble, in this example). IE, the pebble's overall absorbtion and emission rates is appx equivalent to the combined absorbtion and emission rates of its individual constituents.

How's THAT for a definition of "mass" in REAL LANGUAGE. Whether or not it's accurate, I don't know, but thigns make a bit more sense, I think? Though, still multiplying a change in velocity, or a change in change in direction/speed times the resistance to a change in speed/direction, still seems a bit counterintuitive. I'd just wonder if the equations would make more sense in real language if that real language definition of Mass were expanded, or stated mathematically... Dunno. Though it woudl seem to make more sense in terms of what yuo said previously in the thread about, I think it was Power. Soemthign to the effect that it relates to how much energy is expended at the surface of an object... I think that seems to fit rather nicely with the idea of an object taking in and releasing energy as flip sides of the same coin. And as the mitigators of enerfy, acceleration and overall velocity.

This is why I love thinking things out on paper and discussing/debating, occasionally wonderful insigts arise. Thank you for doubting me, ER. I enjoy good debates, since they often reveal things that might otherwise be hidden. Kudos. And I hope my insights were of some small use in a real-world conceptual model of how things work? (Granted I'm still not quite sure what it means to multiply them in an equation. But I think I have a slightly better idea of mass in terms of energy gain/loss and how that plays into acceleration and velocity).