Medium entrainment considered as flow

<b>[Jim] "So, you say gravity changes to suit the problem at hand? "</b>

If I changed my words from
<ul>
"Which way you pick to look at it depends mostly on the problem or the question you have before you ..."

to

"The way you pick to look at it changes it, and determines which of these it is ..."
</ul>
Then your accusation would have some legs.

But I said what I said. Not what you accused me of saying.

===

QUESTION: Why are you deliberately distorting my words?

Gravitation is gravitation.

A is A.

However, we are trying to understand it. And one of the ways we have invented to help us in our quest for such knowledge is to build models of parts of a thing.

In the case of gravitation, we have a model (theory) called force.

It is a way of looking at gravitation. It is a way of thinking about gravtation.

It is not gravitation.

We have another theory called energy.

It is a way of looking at gravitation. It is a way of thinking about gravtation.

It is not gravitation.

We also have a way of thinking about gravitation that we call acceleration.

Gravitation is observed to have this strange property that allows it to accelerate all masses at the same rate.
<ul>
If you just push on a thing, it will accelerate.

You have converted a force (your push) into energy (and/or momentum, depending on how you want to look at it).
<ul>
Nothing about <u>IT</u> has changed because you look at it differently. Only <u>the way you pick to look at it</u> has changed.

Get it?
</ul>
Experience teaches us that it takes a bigger push to accelerate a bigger thing than to accelerate a smaller thing.

Then gravitation shows up and accelerates all things, big and small, at the same rate.

This is different!
And Strange.
</ul>
So this "acceleration" model is particularly usefull for problems that focus on the acceleration-related aspects of a mass in the gravitational "field" of another mass.

You can calculate a "force field" instead of an "acceleration field" if you want to. But then to predict the position or velocity of a mass moving in that field you would need to convert the force into an acceleration before calculating the velocity or position at each point of interest.

But if you are interested in knowing how much force mass A will apply to mass B at various locations in the vicintity of mass A, it makes more sense to calculate a "force field".

Both the force field and the acceleration field of the mass "exist". As does the momentum field and the energy field. You could probably also devise a way to calculate a work field. If it helps you solve a problem, it is a reasonable thing to do. (What? No one else has ever done it that way? If it works, why would you care? The Noble Committee won't care either, as long as the results are obvious. And big.)

But none of these things, these models, is gravitation. So what is gravitation?

===

We do not have a solid answer. We have answers. Plural. Enough that some are in conflict with others. Which is right? That, of course, is TBD.

They cannot all be RIGHT. (Duh.)

But they can all be WRONG.

Did I mention that the physical side of reality is sort of squishy?

The conceptual side of reality, mathematics included, is clean and neat by comparison.

We need all of it, if we are ever going to understand the universe we inhabit. Just keep them in separate buckets. Use them as needed.

And justify your choice.

(If you can. Others will probably not appreciate your use of "intuition". Screw them. But expect to be wrong. There really is a Murphy.)