[David Cooper]

As I´ve said many times, the fact that some condition is NECESSARY for something to happen, doesn´t mean it is necessarily the direct CAUSE ...

There are multiple causes that feed into things and not all of them are direct, but it is certainly not the case that any force from the contact between the two balls caused the first one to run into the second by moving it. It is also not the case that the centripetal force in the string makes the ball on the end of the string move - the bat made it move, and that movement led to the centripetal force being generated to modify the movement of the ball.

With your Logics (?) I could also say: without the second ball being there (perhaps even before first ball started to move ...), " the forces in question would never be generated[": that is the "cause" !!

If you look back at what I said, you might find references to the relative movement of the balls - both of them are causes of the forces that appear between them when they collide. Those forces are not a cause of the relative movement of the balls that leads to the collision.

For anyone new to this thread, this point goes back to a discussion of a ball on a string going round and round an attachment point on a pole where the movement of the ball generates the centripetal and the lesser reactive centrifugal force in the string. No movement of the ball means no forces in the string.

I DID already refute that, but you are unable even to imagine the several facts which occur in the really short time when the momentum (and kinetic energy too) is transferred, as explained on my last post for the "snooker" case.

You have refuted nothing - you merely imagine that you refute things by writing nonsense. The centripetal force in the string does not cause the movement of the ball (that is actually caused by the bat hitting it).

On #217 I said:
"In line with what I said about how things happen when we hit a ball attached through a string to a pole (#202)
"...THAT centripetal force makes the rectilinear movement of the ball change into circular movement, that is, it causes the rotational movement … Quite the opposite of what you say !!”

Your "rotational movement" is my "modification of the movement". To explain that point before, I pointed out that the ball is carrying kinetic energy which it lacks when not moving. The centripetal force does not add kinetic energy to the ball (if the thing the string's attached to at the centre of the apparatus is at rest), but merely changes it's direction of travel. You are incapable of taking in these key details though. Your centripetal force does not cause the movement that I'm referring to and no amount of you muddying the water will make it cause the movement that I'm referring to (and which I've been referring to from the start). And let me remind you that the reason I mentioned this in the first place was to spell out to you a fundamental difference between two different categories of centripetal force. With gravity labelled as centripetal force, that centripetal force is not generated by the orbiting body moving, but acts regardless (with the body stopped), whereas with the ball on the string, the centripetal force there only exists if the ball is moving and disappears if you stop the ball, and that's because the ball's movement generates that centripetal force whereas the orbiting body in the gravity case does not. There is still zero indication of you getting that point even now, many pages after where it was first made.

Since the very first instant an initial tension of the string starts to function as centripetal force (otherwise the ball would continue to move in a straight line), and inertia manifests itself reacting to that initial centripetal force (from the string on the ball), with a centrifugal force (equal, but from the ball on the string end), what initiates the tightening of the string mentioned on what quoted, and subsequent (though transient) increase of both centripetal and centrifugal forces.

No movement of the ball --> no centripetal force generated. Centripetal force will never spring into existence to make the ball move round on the end of the string unless the ball is moving first, and the ball does move first - you can see this from the fact that the centripetal force continues to build after the ball is up to full speed.

What you say, in particular what at the beginning quoted and in italics, is CLEARLY contrary to Newton´s Motion First Law:
"Newton's first law states that every object will remain at rest or in uniform motion in a straight line unless compelled to change its state by the action of an external force. This is normally taken as the definition of inertia. The key point here is that if there is no net force acting on an object (if all the external forces cancel each other out) then the object will maintain a constant velocity. If that velocity is zero, then the object remains at rest. If an external force is applied, the velocity will change because of the force”,
copied from a NASA web site, institution that, among other many feats, several times sent men to the Moon, always within Newton´s Mechanics (apart from any possible nuance Einstein relativity related).

And nothing I have said conflicts with that law, darling. Yet again you're trying to make out that I'm talking about the modification of the movement of the ball rather than the movement of the ball (the fact that it's moving as opposed to being stationary).

Again: you should either elaborate “your” theory and convey it to Physics main institutions, or change your mind wrong “chip” ...

I am giving you the mainstream position, darling - there is nothing in it that would be news to anyone in those institutions.

[rmolnav]

You continue trying to deceive people:

I am giving you the mainstream position, darling - there is nothing in it that would be news to anyone in those institutions.

Months ago I asked you for some scientific references supporting your ideas, and you replied you had not found any article supporting them, because you don´t even look for other people ideas, and your stand is based on what you "see" in nature  (!!)
Therefore, if you now say they are "the mainstream position", you are clearly trying to deceive people (consciously or unconsciously).
For the sake of other people´s possible interest (not yours, I´m afraid), I´ll put it somewhat differently, referring to the INERTIA phenomenon (by the way, another of your "grey" areas), after seeing how clearly NASA article says:

Newton's first law states that every object will remain at rest or in uniform motion in a straight line unless compelled to change its state by the action of an external force. This is normally taken as the definition of INERTIA. The key point here is that if there is no net force acting on an object (if all the external forces cancel each other out) then the object will maintain a constant velocity.

The ball, or any other object, can´t "transfer" its kinetic energy DIRECTLY to other massive stuff (in our case to the string end, where their connection). Kinetic energy is not like, e.g., a ship´s cargo unit, directly transferable (not changing at all) to another ship, though with the necessary help of a crane if too heavy ...
Kinetic energy (mv²/2) and momentum (mv), with a fixed mass, depend only on velocity.
According to Newton´s First Law (what quoted), neither the string end can get (or vary) speed without an additional external FORCE being applied on it, nor the ball´s velocity vector (apart from the way it was previously acquired) can change without an external force being also applied to it ...
Those statements are quite clearly DIRECT consequences of Newton´s First Motion Law ...
AT THE VERY INSTANT of connection, the string has to have an initial tension, however small and whatever its orientation: otherwise the ball would continue to move not changing its velocity vector at all.
That string tension acts at the connection as an force EXTERNAL to the ball, and "forces" the ball´s velocity vector to change direction (if it has a component perpendicular to the ball trajectory; the tangential component only changes velocity size).
Then we have another manifestation of INERTIA: as the ball tries to continue straight but is "forced" to turn, the ball "reacts" with an equal but opposite force exerted on the string ...  (Newton´s Third Motion Law).
That tightens the string (if the other string end is connected to a pole), and the force exerted on each other (string outer end and ball) increases until a dynamic equilibrium is reached (well, with some oscillations due to the elasticity of string and pole).
Those forces, whether you like it or not, are called centripetal and centrifugal forces ... Well, last one is a rather controversial term, but at least could be called "outward" force, "inertial" but quite real. And the "centripetal" one is a quite clear term on "mainstream" Physics. It´s YOUR mindset what is out of mainstream, at least as far as that concept is concerned ...
Again: that "centripetal" force is a FUNCTION that many essentially different forces can exert, not necessarily for ever !! That function is to "force" the velocity vector of an object to TURN, changing a rectilinear movement into a rotational one (or changing the curvature of an already curved trajectory).
LOGICALLY, if for any reason the velocity vector were or became null, the FUNCTION of centripetal force disapears ... But the ESSENCE of the force which was exerting that function might continue unaltered, depending on each case:
- In the case of the string, as it cannot continue tight, the pull on the object disappears.
´- In the gravity case, the gravitational field is not "switched off", and the pull on the object continues, though it ceases exerting any centripetal force FUNCTION ...
But that doesn´t mean those centripetal functions should be calle differently ... Most USA presidents "function" cease when their respective office term ends, but their essence as men continue. But unfortunately JFK was assassinated, and his function as president and his essence as a man ended simultaneously ... Should we call his presidency otherwise ?? Was his "job" different from in the rest of the cases ??
And please, don´t argue again saying

... it is certainly not the case that any force from the contact between the two balls caused the first one to run into the second by moving it ...

as if I had ever said the opposite ... I´ve always said that an initial speed is absolutely NECESSARY ... But, however it was acquired, to curve the trajectory a perpendicular EXTERNAL force is necessary. And, in the string case, it ONLY can be exerted by the string end on the ball, where connected. And that is the DIRECT cause which initiates the turning.
Previous stuff such as the ball itself, its initial speed the bat making it move, are obviously NECESSARY conditions, but neither they are sufficient, nor they DIRECTLY cause the curving of the ball´s trajectory. 

[David Cooper]

You continue trying to deceive people:

I am giving you the mainstream position, darling - there is nothing in it that would be news to anyone in those institutions.

Months ago I asked you for some scientific references supporting your ideas, and you replied you had not found any article supporting them, because you don´t even look for other people ideas, and your stand is based on what you "see" in nature  (!!)
Therefore, if you now say they are "the mainstream position", you are clearly trying to deceive people (consciously or unconsciously).

I know that the method I've been applying is the mainstream one without having to look up specific cases of it being applied. It's common knowledge that gravitational pull is the mechanism, and when I simulate that, it works perfectly. It's also common knowledge that when a simple mechanism works, you should trust it more than some bonkers abstraction where a real force is split up into imaginary components acting from directions far out from the direction to the actual gravitational source. It's just possible that the mainstream position is as daft as yours and that I've overestimated the abilities and rationality of the most competent scientists, but if that's the case, it's their problem rather than mine. I will simply stick to defending good science while opposing bad science.

The ball, or any other object, can´t "transfer" its kinetic energy DIRECTLY to other massive stuff (in our case to the string end, where their connection). Kinetic energy is not like, e.g., a ship´s cargo unit, directly transferable (not changing at all) to another ship, though with the necessary help of a crane if too heavy ...

When they contact you get forces generated, and they transfer the energy, but the kinetic energy is transferred without that energy disappearing out of existence in between and it doesn't take up any intermediate form, so the transfer is as good as direct.

Kinetic energy (mv²/2) and momentum (mv), with a fixed mass, depend only on velocity.
According to Newton´s First Law (what quoted), neither the string end can get (or vary) speed without an additional external FORCE being applied on it, nor the ball´s velocity vector (apart from the way it was previously acquired) can change without an external force being also applied to it ...
Those statements are quite clearly DIRECT consequences of Newton´s First Motion Law ...
AT THE VERY INSTANT of connection, the string has to have an initial tension, however small and whatever its orientation: otherwise the ball would continue to move not changing its velocity vector at all.

Lovely, but you're back to discussing the modification of the movement rather than the fact that the ball's moving. It's the fact that the ball's moving (relative to the thing the string's attached to at the other end) that causes the centripetal force to be generated - not the other way round. No amount of irrelevant bloated waffle about the effects of the centripetal force on the movement of the ball will change that fact.

Those forces, whether you like it or not, are called centripetal and centrifugal forces ... Well, last one is a rather controversial term, but at least could be called "outward" force, "inertial" but quite real. And the "centripetal" one is a quite clear term on "mainstream" Physics. It´s YOUR mindset what is out of mainstream, at least as far as that concept is concerned ...

Time to call out a troll. Here you are making out that I have some other position on that (I do, slightly, in the the correct term is "reactive centrifugal force", and that's the only kind of centrifugal force that actually exists). You are putting on a disgusting display in which you commit fouls. I have told you what these forces are in the string more than once, and here you are acting as if you're in a position to correct me by making out I believe something else. You are just filling up valuable storage space with more and more junk and wasting people's time. It's been interesting studying how you think, but the mysteries that lay there have been well exposed now and there is nothing more to gain from the exercise.

But that doesn´t mean those centripetal functions should be calle differently ... Most USA presidents "function" cease when their respective office term ends, but their essence as men continue. But unfortunately JFK was assassinated, and his function as president and his essence as a man ended simultaneously ... Should we call his presidency otherwise ?? Was his "job" different from in the rest of the cases ??

In the gravitational case, there is no reactive centrifugal course (and indeed, no centrifugal force at all) - that is the key difference, and that's why a naming difference ought to be used so that people like you don't mistake one case for the other and try to shoehorn centrifugal force into a case where it is absent. The only way to put centrifugal force into a gravity case is to use rotating frames, but those are a warped abstraction and not the real physics.

And please, don´t argue again saying

... it is certainly not the case that any force from the contact between the two balls caused the first one to run into the second by moving it ...

as if I had ever said the opposite ...

You have done the exact equivalent of that in the case with the ball on the string by denying that the movement of the ball (the fact that it's moving rather than stationary [relative to the thing the other end of the string's attached to) generates the centripetal (and reactive centrifugal) force, so I can't let you off that hook.

I´ve always said that an initial speed is absolutely NECESSARY ... But, however it was acquired, to curve the trajectory a perpendicular EXTERNAL force is necessary. And, in the string case, it ONLY can be exerted by the string end on the ball, where connected. And that is the DIRECT cause which initiates the turning.

The point is that the movement of the ball (the fact that it's moving) generates the forces in the string and not the other way round - that has been the point from the start and you have consistently rejected it, asserting that it is the other way round because "a movement can't cause a force". All you need to do is correct your position on that, and then we could move on, but you don't want to admit that you were wrong, so you're stuck.

Previous stuff such as the ball itself, its initial speed the bat making it move, are obviously NECESSARY conditions, but neither they are sufficient, nor they DIRECTLY cause the curving of the ball´s trajectory.

Correct, but the key point is that the movement of the ball (the fact that it's moving) causes the centripetal force to be generated, and not the reverse of that. And the only reason I brought this into the discussion was to show up the key difference between this and the gravity case where the gravitational force is not generated by the movement of the moon/planet. I still don't know after all this time if you've yet understood that difference between the cases.

[rmolnav]

you get forces generated, and they transfer the energy, but the kinetic energy is transferred without that energy disappearing out of existence in between and it doesn't take up any intermediate form

It's the fact that the ball's moving (relative to the thing the string's attached to at the other end) that causes the centripetal force to be generated - not the other way round.

The point is that the movement of the ball (the fact that it's moving) generates the forces in the string and not the other way round - that has been the point from the start and you have consistently rejected it, asserting that it is the other way round because "a movement can't cause (DIRECTLY) a force"

(edited, what in bold).

Quote
Previous stuff such as the ball itself, its initial speed the bat making it move, are obviously NECESSARY conditions, but neither they are sufficient, nor they DIRECTLY cause the curving of the ball´s trajectory.(from MY previous post)
Correct, but the key point is that the movement of the ball (the fact that it's moving) causes the centripetal force to be generated, and not the reverse of that

ALL quoted paragraphs have same error: NO single force is DIRECTLY caused by the movement, though centrifugal forces are generated INDIRECTLY by it, because they are INERTIAL reactive forces: the way the ball shows its tendency to carry on straight, when any force ACTING as centripetal force is “forcing” it to turn.
But, as I´ve said many times, to change in any way the velocity vector of ANY object, it is ABSOLUTELY necessary that a net EXTERNAL force is exerted on it (Newton´s First Motion Law). OTHERWISE IT WOULD CONTINUE ITS RECTILINEAR PATH !!
In the case of the string and ball, that initial external force (the ball already having a speed, whatever the way it got it) ONLY can come from an initial tension of the string ... 
During some time after initial instant, inertial centrifugal forces, pulling outwards on string connection to the ball, increase string tension, and that (not directly the movement) generates an INCREASE of centripetal force, what produces a further curving of the trajectory …
So, NO MOVEMENT (OR CHANGE OF MOVEMENT) CAUSES DIRECTLY ANY FORCE: there are ALWAYS more or less “hidden” FORCES (original or directly originated by other forces), that CAUSE OR MODIFY movements …
And "kinetic energy is transferred WITH that energy "disappearing" out of existence in between …”:  it “DOES take up an intermediate form” (only part of it in the string case) : WORK transferred during any infinitesimal time, equal to exerted FORCE multiplied by the infinitesimal covered space.
Logically that force causes acceleration, what increases velocity. The transference is usually analyzed, as I already said, in terms of “impulse” (force multiplied by time), what causes a momentum increase (mass multiplied by velocity).
For anybody interested, what follows is quoted from:
https://www.khanacademy.org/.../physics/...momentum/momentum.../what-are-mome…
"Momentum is a measurement of mass in motion: how much mass is in how much motion. It is usually given the symbol p.
By definition,
p=m⋅v
Where m is the mass and v is the velocity. The standard units for momentum are kg⋅m/s, and momentum is always a vector quantity. This simple relationship means that doubling either the mass or velocity of an object will simply double the momentum.
The useful thing about momentum is its relationship to force. You might recall from the kinematic equations that change in velocity Δv
can also be written as a⋅Δt.
We can then see that any change in momentum following an acceleration can be written as
Δp​=m⋅Δv=m⋅a⋅Δt=F⋅Δt​
Impulse is a term that quantifies the overall effect of a force acting over time. It is conventionally given the symbol J and expressed in Newton-seconds.
For a constant force, J=F⋅Δt.
As we saw earlier, this is exactly equivalent to a change in momentum Δp. This equivalence is known as the impulse-momentum theorem. Because of the impulse-momentum theorem, we can make a direct connection between how a force acts on an object over time and the motion of the object.".
ALL THAT SAID, we can see that centripetal force FUNCTION of the string tension starts with a previously existing initial tension, and increases thanks to the fact that reactive centrifugal force (not directly the movement) increases string tension ...
Ball velocity vector change´s DIRECT causes are always FORCES.
In any case, all that doesn´t actually occur in nature: it is just an artificial, short-lived "experiment" ... Gravity and friction would soon bring everything to a stop.
To make it last long, we would need an additional supply of energy, e.g. what an athlete does when hammer-throwing ... The athlete leans backwards a little, and that way hammer-athlete couple rotates as a single system round their common center of mass, located at forward side of the athlete.
That scenario is dynamically very, very similar to the one of earth-moon system (though the athlete has to pull the wire with some tangential component to compensate energy losses). Not only the string case "needs" the movement for the appearance of the centripetal force: in the gravity case, previously existing pull also "needs" the movement to get its centripetal force FUNCTION (not just a "label" as you´ve said so many times) ...
In both cases the rotating elements are "forced" to follow a curved path, because their natural inertial tendency is to maintain their velocity vectors constant (Newton´s First Motion Law). ONLY a force can exert that FUNCTION, and it is called CENTRIPETAL FORCE, whatever its essential nature and/or origin (string tension, gravity, friction road/tyres, the cant of a curved road, hydraulic or pneumatic pressure differences on fins or wings, etc).
And the caused centripetal accelerations always make inertia somehow manifest itself as a "tendency" of the rotating objects to oppose to those accelerations ... in referred cases as a centrifugal force, or "outward" force if you prefer. Remember what I quoted about Einstein ideas on the issue:
"Einstein warmed to the idea that the gravitational field of the rest of the Universe might explain centrifugal and other inertial forces resulting from
acceleration.’ ...
though I dare say that is a too far fetched idea …"
But he considered a fact what in bold !!
And he even somehow identified inertia with gravity !!
After all, you might be right when saying ONLY gravity matters for tides ... as long as we include in "gravity" the "other side of the coin", INERTIA, and its manifestation as centrifugal force. 
Well, in that field (relativity and essence of "gravity" according to Einstein) I must admit I can´t be more assertive: that is really a "grey" area to me ...

[David Cooper]

ALL quoted paragraphs have same error: NO single force is DIRECTLY caused by the movement, though centrifugal forces are generated INDIRECTLY by it, because they are INERTIAL reactive forces: the way the ball shows its tendency to carry on straight, when any force ACTING as centripetal force is “forcing” it to turn.

You're not getting away with that. Right at the start when I made this point, I said the movement causes the force to be generated and you denied that. Adding the word "directly" into that doesn't rescue you from your wayward attack. You were plain wrong. And you're still avoiding the bigger point that this is about: the fact that in gravity cases there is no centrifugal force of any kind involved at all. Anyway, I'd like to thank you for making yourself available to study - it has been worthwhile, but there is clearly nothing further to be gained from continuing with this and I've got a growing mountain of important work to get on with, so I'll just let you go on defecating on the end of this thread forever. I've given up on the idea of building a simulation of your method as you don't understand your own mechanism sufficiently well to set it out in the detail required to make that possible. Anyway, you can bury everything that's happened under a mountain of garbage and no one sane will ever dig deep enough to find what actually happened here.

A few comments to close my involvement though. You say that a movement can't directly cause a force, but that means that a force can't directly cause a movement either - the two things are symmetrical, and whatever you're putting in between them is a fiction.

Not only the string case "needs" the movement for the appearance of the centripetal force: in the gravity case, previously existing pull also "needs" the movement to get its centripetal force FUNCTION (not just a "label" as you´ve said so many times) ...

It's just a label, darling - the gravitational force is not changed by the orbiting thing being made to move round the other body. It only needs the movement in order for it to qualify for your silly label.

Farewell (hopefully forever).

[rmolnav]

If D.C. intention is not to reply any further post from me, I´m not going to refute now (or "trying" to refute ...) any of ideas directly ...
But I consider it would be interesting to others to remember now my stand about one of our main differences, directly related to the title of this thread. Time and time again he has posted paragraphs similar to what on his last post::

... And you're still avoiding the bigger point that this is about: the fact that in gravity cases there is no centrifugal force of any kind involved at all.

Many times I´ve said INERTIA manifests itself in different ways, depending on details of the "scenario", basically on the type and degree of "freedom" the considered object has (not always there is a fully "free fall" ...)
In many cases gravity eventually makes the considered object fall onto the object causing the gravitational field ... We could say the pull "wins" the gravity-inertia "battle": no permanent inertial effect ...
In "proper" orbiting cases, that "battle" keeps being fought: neither gravity produces the collision, nor orbiting object is able to continue straight, its natural inertial tendency. Now I won´t repeat what several times I said (e.g., #382) relative to "inertial" and "not inertial" reference systems ...
In our case (earth-moon dynamic system), as the moon is not on a fix location, but also rotating around the barycenter (a movement within the realm of the dynamics of the system), the movement of the earth can´t be considered a "proper" orbiting round the moon ...
Similarly to the fact that moon is "tidal locked" (same side of it is always facing our planet), we could say both are "gravitational locked" to each other: the "couple" behaves like a single system, "orbiting" together round the sun (more exactly, the "common" center of mass or barycenter).
Should anybody be interested on a further explanation, please have a look at #362 and #364 (they are rather short posts).
THAT IS WHY I said:

... The athlete leans backwards a little, and that way hammer-athlete couple rotates as a single system round their common center of mass, located at forward side of the athlete.
That scenario is dynamically very, very similar to the one of earth-moon system (though the athlete has to pull the wire with some tangential component to compensate energy losses)...
In both cases the rotating elements are "forced" to follow a curved path, because their natural inertial tendency is to maintain their velocity vectors constant (Newton´s First Motion Law). ONLY a force can exert that FUNCTION, and it is called CENTRIPETAL FORCE, whatever its essential nature and/or origin (string tension, gravity, friction road/tyres, the cant of a curved road, hydraulic or pneumatic pressure differences on fins or wings, etc).
And the caused centripetal accelerations always make inertia somehow manifest itself as a "tendency" of the rotating objects to oppose to those accelerations ... in referred cases as a centrifugal force, or "outward" force if you prefer.

If the total pull of the moon (at current average distance) were distributed proportionally to the mass of each earth´s particle (with null so called "differential gravity"), centrifugal force due to the revolving of the earth round the barycenter would cause a decrease of sea level at sublunar area, what I´ve sometimes called a "negative" bulge (remember that earth doesn´t "rotate" but "revolves" round the barycenter), and an increase at antipodal area ... (in this imaginary case due only to centrifugal force).
But, being moon´s pull not uniform, at sublunar area the bulge is actually "positive" (moon´s pull there is bigger than centrifugal force), and the antipodal bulge keeps being "positive" (though smaller than if with uniform pull), because centrifugal force is bigger than moon´s pull there.
We should not forget that own earth gravity, the one which makes earth basically spherical, is several million times bigger than above considered forces ... Where the net result of those forces (moon´s pull and centrifugal force, always parallel to moon-barycenter-earth straight line) has the sense opposite to water own weight, this weight kind of decreases very, very slightly ... and bulges build !! 
Apart from those very tiny "decreases" of water weight at bulge central areas, we have to keep in mind that mentioned net "tidal" forces (addition of moon´s pull and centrifugal force vectors), on the rest of closer and further hemispheres have tangential (to ocean surface) components, that, not having any opposition from own water weight, can and make the water move towards central area of each hemisphere, and water piles there. That contributes to the bulge formation not less than above mentioned very tiny "lightening" of water where bulges build up ...
My stand is also in agreement with some most knowledgable physicists and astronomers, but now I won´t bring any comment on that ... Perhaps another day, for people to remember.
If D. C. reads this, he needs not to reply ... I don´t mind repeating here he considers centripetal force just an artificial "label" I put on gravity, also artificial the splitting of forces into their orthogonal components, centrifugal force what quoted at the beginning of this post, and therefore that only "differential gravity" counts for tides. And he doesn´t care about referred scientist stands ...
Each reader is logically "free" to take sides …

[David Cooper]

I wish to withdraw my troll accusation and aplolgise for making it - rmolnav's post above displays a respectability that deserves full recognition, so we ought to part on better terms. I cannot justify putting any more time into this thread though, so I am out. And if you, rmolnav, celebrate anything like Christmas at this time of year, I wish you a good one.

[Colin2B]

May I congratulate you both on being able to keep this going for so long with interesting arguments on both sides.
Much more engaging than Wimbledon.

Merry Christmas to both of you 

[rmolnav]

D.C. and Colin2B:
Thanks for your words, and Merry Christmas and Happy New Year !
D.C.: beyond any "political correctness", I beg your pardom for my frequent rather "strong" words ...
Colin2B: I consider this thread should be kept open, just in case somebody else wanted to send some comments, or to ask any further question relative to the issue ... And thank you again !

[rmolnav]

I beg your "pardom"

Pardon, sorry.

[Colin2B]

No plans to close this. Despite the strongly expressed feelings the content is useful.

[RobC]

Is this the answer?

[rmolnav]

Is this the answer?

I learnt about that video long ago, watched it, and sent them many posts refuting their explanation ...
On the one hand, they don´t tackle the heading question of our thread: they deal only with the sublunar bulge.
On the other hand, they "touch" a correct idea I´ve also brought here many times, last one: 

Apart from those very tiny "decreases" of water weight at bulge central areas, we have to keep in mind that mentioned net "tidal" forces (addition of moon´s pull and centrifugal force vectors), on the rest of closer and further hemispheres have tangential (to ocean surface) components, that, not having any opposition from own water weight, can and make the water move towards central area of each hemisphere, and water piles there. That contributes to the bulge formation not less than above mentioned very tiny "lightening" of water where bulges build up ...

...that is, water moves towards where the two opposite bulges build from areas as far as 90º away ...
But they talk about "squeezing" on areas that distance away, or near there, where moon´s pull has an inward vertical component, what theoretically could "squeeze" the oceans, and "push" water particles towards sublunar area. But:
1) Being the moon some 70 earth radius away (if I remember right), that area is very, very narrow.
2) The NET "tidal" force there (whether you consider centrifugal forces added to moon´s pull, or you consider the so called "differential gravity") is almost null ...
3) Vertical components of those forces are proportional to the sine of very, very small angles, that is, near to null.
Therefore, that effect, if any, would be insignificant !
Quite another thing is the effect of net tidal PULL on the rest of the hemispheres, mainly on intermediate areas (let us say from 75º to 15º away), that ...
1) ... has values neither maximum nor near to null, but with not near to null TANGENTIAL components,
2) ... doesn´t have the opposition of own earth´s pull (as where bulges build),
3) ... and therefore it causes water movement towards sublunar and antipodal areas, where water very, very tiny "lightening" (due to tidal forces) ALONE could actually cause only a small fraction of the water level gradient we get at both hemispheres !!

[rmolnav]

WHAT FOLLOWS is a post I sent minutes ago to the thread "What is centrifugal force".
I´ve decided to put it here too, because the issue in directly connected to tides.
On another post I´ll add some "singularities" to be kept in mind in the case of earth´s revolving around earth-moon barycenter ... Centrifugal inertial effects are not quite the same as what exposed about the moon, especially in the case of sea water, not existing on the moon ...:

"Since my last post I´ve frequently found myself ruminating on our issue, trying to find better ways to convey my stand.
On this thread and on “Why do we have two high tides a day”, many times I´ve referred to the different ways inertia manifests itself, depending on the type and degree of “freedom” to move considered material stuff actually has …
The more I ruminate on the issue, the clearer I find that the root of the confusion is that the term “centrifugal force” is used too broadly, even in cases where certainly a “centrifugal effect” does exist, but not as a real newtonian force … But in other cases that centrifugal effect appears, totally or partially, as a real force.
A general term to cover all scenarios could be “centrifugal inertial effect” (CIE?), that always is present if the trajectory of any massive stuff is curved, whatever the cause of that curved path … I´ll try and elaborate as follows.
We all know Newton´s Motion Laws. But I´m afraid not all keep in mind those laws are just the consequence of the basic Physics phenomenon of INERTIA: massive objects (and any part of them) always have a TENDENCY to maintain constant its current velocity vector, and they show a RESISTANCE to any agent trying to accelerate considered massive stuff. Those laws put it in terms of forces: f=ma (2nd law), being 1st law when f=0, and 3rd one the necessary consequence when considering two directly interacting objects.
We can analyze any possible case starting directly from INERTIA phenomenon, instead of using the “tool” of Newton´s Laws, not breeching them though: it´s a kind of other side of the coin …
In some cases, that RESISTANCE shows up as a real FORCE, but certainly not always.

The term CENTRIFUGAL always refers to an outward “tendency” to move, implying the existence of a “center”: the center of a circular path followed by an object, or at least the center of curvature of its CURVED PATH.
It´s convenient to separate cases with direct physical connection between interacting objects (A), from cases when gravity is involved (B).
A) Hammer throwing: the “hammer”, as a whole, is being centripetally accelerated. INERTIA tends to make it go on the tangent, the cable (and the athlete) don´t let it move straight, and the inertial RESISTANCE to being accelerated inwards appears as a real CENTRIFUGAL FORCE exerted by the hammer on the wire´s end … (I´m not considering now internal forces, that would be different if we had a sling instead, and form a “field” of real centrifugal forces, exerted between contiguous particles …).
It´s what David Cooper calls “reactive centrifugal force”. Similar things can be said about other cases such as wheeled wagons on a railway, vehicle rubber tires on road surface (with or without banking), etc., 
B) When gravity is involved, as it changes with distance, it´s paramount to distinguish cases when those changes are practically null (due to the rotating object negligible size, compared with distance to the object causing the gravitational field - e.g.: artificial satellites), from the rest.
B.1) In the first case the objects are in a pure “free fall”. All their particles are accelerated the same. Inertial RESISTANCE to being accelerated (proportional to mass and given acceleration) is precisely what makes necessary the existence of the gravitational pull f=ma: otherwise the object would continue straight.

But now we don´t have even a “reactive” centrifugal force: acting centripetal force, the gravitational pull at that location, is independent from the object´s inertia … If in some moment F were not equal to ma, the object would be free to change orbit (certainly a case quite different from hammer-throwing).
B.2) The simplest case is our moon rotation around earth-moon barycenter.
INERTIA makes every moon´s particle tend to keep moving straight, but all those particles are forced to follow circular paths.
The further the particle, the bigger the radius, and the bigger the acting centripetal force mω²r.
Inertial RESISTANCE to being accelerated is proportional to ma. If the particles were in a real free fall, they would be free to adjust their orbits to the acting gravitational pull at their location, that varies inversely to the square of the distance.
But that is not possible. If, e.g., we transversely “cut” the moon into too halves, the further one is being centripetally accelerated more than what earth´s pull would cause on that “hemimoon” if it were really free to move. Therefore, ALWAYS existing inertial RESISTANCE to being accelerated is only PARTIALLY compensated by earth´s gravitational pull, the unique force “external” to the moon. That fraction of that inertial RESISTANCE, as on case B.1, doesn´t cause any additional centrifugal effect, let alone force.
But the inertial RESISTANCE not “compensated” that way is still present, and, similarly to what in the hammer throwing case (A), it causes an outward pull on adjacent inner half moon. That is a real CENTRIFUGAL FORCE, quite similar to the one exerted by the hammer on the wire´s end. It “forces” closer half of the moon to keep the common orbit, instead of a smaller one that would match with the stronger earth´s pull on closer “hemimoon”.
On any other transverse section similar things happen, and the moon is stretched in the direction of the straight line earth-moon, what is also called “tidal effect”. By the way, directly connected with the fact that the moon is “tidal locked” to earth (closer and further mentioned halves don´t change, apart from some very tiny “oscillation”).
So, I consider quite opposite stands:
1) In all cases with curved paths real centrifugal forces are present,
2) The fact of having a curved path doesn´t imply the existence of real centrifugal "effects", and real centrifugal forces only appear in cases similar to hammer throwing (never when gravity is involved),
are both erroneous.
And the "invention" of a fictitious centrifugal force for cases when a rotating frame of reference is used doesn´t help diminish confusion ... That just adds something to cause the REAL inertial effects that, logically, disappear when rotation "ceases", as actually happens relatively to mentioned type of frame (precisely called "non inertial" !!)".   

[David Cooper]

But the inertial RESISTANCE not “compensated” that way is still present, and, similarly to what in the hammer throwing case (A), it causes an outward pull on adjacent inner half moon. That is a real CENTRIFUGAL FORCE, quite similar to the one exerted by the hammer on the wire´s end. It “forces” closer half of the moon to keep the common orbit, instead of a smaller one that would match with the stronger earth´s pull on closer “hemimoon”.

If we think about an object sitting near a black hole, the gravity pulls on the object, and it does so more strongly on the near side of that object than the far side, so a tension force appears within it (which might pull it apart in the process known as spaghettification). That tension force is not any kind of centrifugal force. That force will be opposed by an opposite force which is likewise not any kind of centrifugal force.

If the planet is going round the black hole rather than falling towards it, these opposed tension forces are still acting within it, but their cause is exactly the same as in the non-rotating case. If you want to call the gravitational force centripetal force, what are you going to call the tension force that acts in the same direction? Is it centripetal force too? Maybe it is - it's just the force being converted to a different from and transferred on, so yes, and that logically requires you to call the opposing tension force reactive centrifugal force.

However, all these forces are driven by direct gravitational pull and the rotation aspect is a complete irrelevance to them, so if you want to provide people with a real understanding of what's going on, you have a duty to avoid using words like centripetal and centrifugal in the explanation.

Furthermore, if you still want to assert that any tidal bulge is caused in some way by "centrifugal force" based on misnaming a force as reactive centrifugal force (when it's really just reacting to direct gravitational pull), you still aren't managing to pin that label to anything that builds a bulge, not least because it would be attempting to prevent a bulge appearing rather than doing anything to help form one.

[rmolnav]

I didn´t replied last post because the discussion continued on the thread "What is centrifugal force?", and most of what posted was about centrifugal force in general, not to its relation with tides. If interested, you can follow it there.
But on a recent post D.C. referred to tides too, and I replied to that respect:
"Many, you included, say only differential gravity can cause tidal bulges …
Let us imagine moon´s gravity were constant across the earth, maintaining moon´s total pull, and therefore actual distances and moon-earth “dancing” …
The “tendency” of earth revolving particles (both solid and water) not to change their velocity vectors (INERTIA) would cause two “tidal” bulges, but BOTH in the sense opposite to the moon (opposite to the centripetal force, that is, always parallel to line earth C.M. - barycenter - moon C.M.).
That implies that the sublunar “bulge” would actually be the opposite: earth radius decreases at that hemisphere …
That would be similar to what happens if, with our hands, we make a cap of tea on a table follow uniformly a circular path …
As I´ve said on "Why do we have two high tides a day?" thread many times, those centrifugal inertial "effects", added to what caused directly by the varying gravitational moon´s pull (inversely proportional to the square of the distance), is what causes the real tidal bulges !!
Remember what Einstein thought:
"Einstein warmed to the idea that the gravitational field of the rest of the Universe might explain centrifugal and other inertial forces resulting from acceleration".
Do you know better than Einstein ?? Or do you think that gravitational pull, acting as centripetal force (by the way, your "grey" area ...) doesn´t cause centripetal acceleration, and subsequently neither centrifugal forces nor other inertial "effects" are present ??
If so, please kindly give all of us your "reasons", instead of just saying "your imagined centrifugal effects don't exist in the gravity case"

[David Cooper]

If you want to bring Einstein into it, you should use relativity. Relativity shows that straight-line differential gravity provides the same explanation regardless of the amount of movement perpendicular to the direction of the gravitational pull, and that leaves no possible role for centrifugal force.