The Flat Earth Society
Flat Earth Discussion Boards => Flat Earth Theory => Topic started by: pricelesspearl on October 11, 2019, 09:06:47 PM
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How would one calculate the rate of acceleration of an object on an inclined plane in a UA scenario?
With gravity (assuming no friction or applied force for simplicity), you begin by finding the perpendicular and parallel components of gravity acting on the object. Since the normal and perpendicular forces will cancel each other out, we are left with only the parallel component of gravity acting as the net force accelerating the object.
My assumption would be that one would use the same process for UA. The directions of the UA force and normal force would be reversed from the directions of gravity and the normal force, but since they would still cancel each other out, it wouldn’t affect the calculations. However, using the same process would mean that instead of gravity acting as the only force accelerating the object, UA is only force accelerating the object.
Objects require force to accelerate and they will always accelerate in the direction of net force…so how would anything slide down an incline in a UA environment?
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How would one calculate the rate of acceleration of an object on an inclined plane in a UA scenario?
The same way you would in RET, as per the Equivalence Principle.
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The same way you would in RET, as per the Equivalence Principle.
I agree the numbers would look the same. The difference would be the net force you end up with would be UA instead of gravity. How does the equivalence principle explain how UA…an upward force…can be responsible for accelerating something downhill?
This is what the calculations with gravity would look like.
Net Gravitational force 10kg @ 20 ⁰
Fnorm = 10.000 * 9.810 * cos(20) = 92.184N
F⊥= 10.000 * 9.810 * cos(20) = 92.184N
F// = 0.000 * 9.810 * sin(20) = 33.552N
The normal and perpendicular forces cancel each other out, so the net gravitational force is 33.552N. The net UA force would be the same, but in the opposite direction. How does that account for being accelerated downhill?
Net Gravitational force 10kg @ 30 ⁰
Fnorm = 10.000 * 9.810 * cos(30) = 84.957N
F⊥= 10.000 * 9.810 * cos(30) = 84.957N
F// = 10.000 * 9.810 * sin(30) = 49.050N
The normal and perpendicular forces cancel each other out, so the net gravitational force is 49.050N...same question as above.
Interesting observation…the net gravitational force increases as the angle increases. It’s almost as if the magnitude of the net gravitational forces on something change in response to how level it is. I wonder if there is some device that could demonstrate that?
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How does the equivalence principle explain how UA…an upward force…can be responsible for accelerating something downhill?
This is the same argument as your spirit level fiasco. You do not seem to understand that acceleration is relative to a frame of reference. There will be no helping that until you brush up on high school physics.
Your question boils down to "What is the equivalence principle?" You're well capable of Googling that.
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Your question boils down to "What is the equivalence principle?" You're well capable of Googling that.
I understand EP enough to know that in order for it to apply, in one reference the object is at rest and in the other, the object is being accelerated. However, the example I have given, the object is being accelerated in both references.
UA explains why, if I released a box from a height, the box would appear to fall to the ground, when in reality, the ground is rising up to meet the box.
It would not explain why a box would accelerate down an inclined plane if placed on an inclined plane that was already sitting on the ground.
Those are two different things. The ground is not rising up to meet the box
Let S1 be accelerated in the direction of its X axis, and let g be the (temporally constant) magnitude of that acceleration. S2 shall be at rest, but it shall be located in a homogeneous gravitational field that imparts to all objects an acceleration –g in the direction of the X axis. As far as we know, the physical laws with respect to S1 do not differ from those with respect to S2; this is based on the fact that all bodies are equally accelerated in a gravitational field. At our present state of experience we have thus no reason to assume that the systems S1 and S2 differ from each other in any respect, and in the discussion that follows we shall therefore assume the complete physical equivalence of a gravitational field and a corresponding acceleration of the reference system.
The fact that an object at rest in a UA reference will appear to behave the same way as an accelerated object in a gravity reference does not mean an object being accelerated in an UA reference would appear to behave the same as an object being accelerated in a gravity reference
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I understand EP enough to know that in order for it to apply, in one reference the object is at rest and in the other, the object is being accelerated.
Yes, that's the problem. You "understand" it so well that the very first part of your attempt at describing it is wrong.
There's no way around this. You need to learn physics before you can meaningfully argue it. Again, nothing to do with FE vs RE, and everything to do with understanding of the fundamentals.
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You "understand" it so well that the very first part of your attempt at describing it is wrong.
You mean this part?
Let S1 be accelerated in the direction of its X axis, and let g be the (temporally constant) magnitude of that acceleration.
I guess you understand EP better than Einstein, since that is a direct quote from him.
https://www.mathpages.com/home/kmath622/kmath622.htm
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You mean this part?
Yes, obviously I meant something I didn't quote, and not what I explicitly quoted prior to replying. Sigh.
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You mean this part?
Yes, obviously I meant something I didn't quote, and not what I explicitly quoted prior to replying. Sigh.
The two statements were substantively the same. And they are both correct.
This is the so called Equivalence hypothesis, which in other words states that it’s impossible to tell the difference between an object at rest in a gravitational field or an accelerating object in free space, where the acceleration is generated by a force equal to the gravitational field.
https://esc.fnwi.uva.nl/thesis/centraal/files/f31871018.pdf
A state of rest in a homogeneous gravitational field is physically indistinguishable from a state of uniform acceleration in a gravity-free space. However, in the Universal Relativity, only the change in the geometry has to be taken into account. An object moving in space at an acceleration g, and an object at rest under gravitation g are not equivalent; the principle of equivalence does not hold.
(Note here that the author is arguing that under Universal Relativity, EP would not hold. The point of the quote is how the author defines EP)
https://www.researchgate.net/publication/276105151_Universal_Relativity_Absolute_Time_and_Mass
A charged particle at rest in a gravitational field, such as on the surface of the Earth, must be supported by a force to prevent it from falling. According to the equivalence principle, it should be indistinguishable from a particle in flat space being accelerated by a force
https://en.wikipedia.org/wiki/Paradox_of_radiation_of_charged_particles_in_a_gravitational_field
Mid-slide UA could account for the object appearing to accelerate downwards, when in reality the inclined plane was rising...not really sure about that but will accept it for the sake of argument...but it would not account for what caused the object to begin accelerating downwards to begin with.
If I release an object in a UA environment, it will not accelerate it downwards. It will remain stationary until the floor makes contact with it, but for some reason UA will accelerate an object downwards when it is on an inclined plane. Not sure how EP turns UA into a force that accelerates objects down in one case and not the other.
What you are not getting is that EP only applies to free falling bodies…bodies not subject to any forces, and an object on an inclined plane, is by definition is not a free falling body.
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Well, sorry. Until you learn the basics, I won't be able to help you, no matter how much you protest. If your misunderstandings of simple physics applied in reality, it would break RET.
As always, you can easily test your hypothesis to see just how blatantly confused you are. You can place an item on an inclined plane, and accelerate the system upwards by hand. You can try this with different objects and inclines to see how the resultant forces interact with friction. You could make a fun-filled day out of it.
You should also have a read on how to represent problems in inertial and non-inertial frames of reference. Your confusion between the two is the source of your "why are things not accelerated downwards?" conundrum.
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You should also have a read on how to represent problems in inertial and non-inertial frames of reference
Thanks, but I am satisfied with my understanding. The preferred refence frame in GR is the Lorentz frame, which by definition is a free falling (inertial) frame of reference.
EP simply does not apply in the situation I have described. A supported object is not by definition in free fall and EP does not apply.
Lorentz Frames
The conclusion is that we need to abandon the entire distinction between Newton-style inertial and noninertial frames of reference. The best that we can do is to single out certain frames of reference defined by the motion of objects that are not subject to any nongravitational forces. A falling rock defines such a frame of reference. In this frame, the rock is at rest, and the ground is accelerating. The rock’s world-line is a straight line of constant x = 0 and varying t. Such a free-falling frame of reference is called a Lorentz frame. The frame of reference defined by a rock sitting on a table is an inertial frame of reference according to the Newtonian view, but it is not a Lorentz frame
EP is much more nuanced than your wiki suggests or that you want to pretend it is so that you can use it as your response to any difficult question. There are multiple versions with multiple interpretations that even leading academics can’t seem to agree on. Whether or not it applies only infinitesimally is hotly debated as well as what defines “locally”, but all agree that to the extent tidal effects are measurable it doesn’t apply and that it only applies to an isolated observer.
What they all agree on is that it does not apply all the time, in every situation, to everything.
If you can’t or won’t address why you believe your interpretation is correct or why it should apply, don’t be surprised when you get push back. “Because EP” is a pretty low effort response.
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Dude, you are just wrong, whether the incline is pushing up or the ball is rotating down the result looks the same. I’m a REer and I know this to be true. Once you complete high school physics you should be able to visualize it too.
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Dude, you are just wrong, whether the incline is pushing up or the ball is rotating down the result looks the same. I’m a REer and I know this to be true. Once you complete high school physics you should be able to visualize it too.
Like a said a few post above, if just seeing it mid-slide, you are right. But UA doesn't explain why it would begin to slide in the first place I know enough about physics to know that an object at rest will not move unless a force is applied to it.
If I simply released an object in a UA environment, there is no force to move it. It will just remained suspended until the floor made contact. If I place it on an inclined plane instead of releasing it, there is still no force to move it. No force means no movement. That is high school physics.
And I am not a dude.
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And I am not a dude.
In that case, madam, I think the point you are failing to understand about the UA theory is that the earth itself shields us from the force which powers it.
So the earth is accelerated upwards but if you jump then you are not affected by the force of UA - if you were then you wouldn't fall.
So if something is on an inclined plane then it's the acceleration of the earth caused by UA which imparts the force which causes the ball to move.
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Dude, you are just wrong, whether the incline is pushing up or the ball is rotating down the result looks the same. I’m a REer and I know this to be true. Once you complete high school physics you should be able to visualize it too.
Like a said a few post above, if just seeing it mid-slide, you are right. But UA doesn't explain why it would begin to slide in the first place I know enough about physics to know that an object at rest will not move unless a force is applied to it.
If I simply released an object in a UA environment, there is no force to move it. It will just remained suspended until the floor made contact. If I place it on an inclined plane instead of releasing it, there is still no force to move it. No force means no movement. That is high school physics.
And I am not a dude.
Dude, tidal forces are pretty much the death of UA and there is no even remotely Ad Hoc explanation for them, except perhaps some weird Sandokhan voodoo. But your inclined plane thought experiment shows a lack of understanding of the discussions on this site.
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So the earth is accelerated upwards but if you jump then you are not affected by the force of UA - if you were then you wouldn't fall.
That’s not what the wiki says. It says that when you jump…you don’t fall…the earth catches up. Things don’t” fall” in UA, that is the point. I don't see why an object being released would be affected any differently by UA than someone who is jumping. Both should just remain suspended, with no force acting upon it until the earth "catches up".
When you jump, your upward velocity is for a moment, greater than the Earth's so you rise above it. But after a few moments, the Earth's increasing velocity due to its acceleration eventually catches up
In addition, nobody has really addressed the initial question I asked is how you would calculate the rate of acceleration. As I pointed out in a previous post
The calculations should be the same except the direction of the UA force and normal force would be opposite of gravity and normal force.
So let’s compare the calculations for both, using negative to indicate the gravity/normal direction and positive to indicate the UA/normal direction.
Using negative for gravity to calculate the net force on a 10k object at a 20 ⁰ angle
Fnorm = 10.000 * -9.810 * cos(20) = -92.184N
F⊥= 10.000 * -9.810 * cos(20) =-92.184N
F// = 0.000 -.810 * sin(20) = -33.552N
So in gravity the net force on the object would be -33.552N…IOW, down, in the negative direction
Using the same process using positive for UA to calculate the net force on a 10k object at a 20 ⁰ angle
Net UA force 10kg @ 20 ⁰
Fnorm = 10.000 * +9.810 * cos(20) = +92.184N
F⊥= 10.000 * +9.810 * cos(20) =+92.184N
F// = 0.000 -.810 * sin(20) = +33.552N
So with UA, the net force on the object would be +33.552N…IOW, up in the positive direction.
So using the same calculation formula, with UA the object is actually being pushed up. So if UA is actually responsible for accelerating it down, how would you calculate it?
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But calculating the excess force is not the end of the problem, you have to assess what happens with that excess force. Once you figure that out you should understand that both situations result in what looks like a ball rotating in the direction of the declining slope.
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But calculating the excess force is not the end of the problem, you have to assess what happens with that excess force. Once you figure that out you should understand that both situations result in what looks like a ball rotating in the direction of the declining slope.
The excess force is what accelerates the object and it will always accelerate it in the direction of the force. If the excess force is in the negative direction, it will accelerate it in proportion to the mass in the negative direction. If the excess force is in the positive direction, it will accelerate the object in the positive direction.
Acceleration is produced by a net force on an object and is directly proportional to the magnitude of the force, in the same direction as the force, and is inversely proportional to the mass of the object.
Acceleration = Force/mass (a = F/m)
http://www.csun.edu/~psk17793/S9CP/S9%20Acceleration.htm
Using the same figures as above :
Gravity a=-33.552/10.00
a= -3.3552 in negative or downward direction for gravity
UA a = 33.552/10.0
a=3.3552 in the positive or upward direction for UA
If there is another way to calculate it so that UA actually accelerates something down, perhaps you can provide it.
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So you think you can’t spin a wheel in same direction by spinning upwards on the left side or downwards on the right side?
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That’s not what the wiki says. It says that when you jump…you don’t fall…the earth catches up. Things don’t” fall” in UA, that is the point.
Ok, fine. It was a mistake to use the word “fall”. I used it because that’s how we think of it. But ok, try this. Let’s say you put a ball on an inclined plane in a weightless environment, so no gravity is acting. The ball stays where it is, yes?
Now imagine you accelerate the inclines plane upwards. The plane now exerts a force upwards on the ball. So the ball is pushing down on the plane. But because the plane is inclined a part of that force acts down the slope, so it moves (assuming that force is greater than the friction force). No?
If that upward acceleration produces the same force as gravity does in conventional physics you’d get the same result.
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Now imagine you accelerate the inclines plane upwards. The plane now exerts a force upwards on the ball. So the ball is pushing down on the plane. But because the plane is inclined a part of that force acts down the slope, so it moves (assuming that force is greater than the friction force). No?
No. I explained this is in an earlier post. The force the object exerts on the plane is cancelled out by the perpendicular force of the accelerating force. The only force left to accelerate the object is the force parallel to the incline, and it will accelerate the object in the direction of the force.
I have already showed the calculations using the standard formula for determining the force on an object on an incline in a gravity environment. If you use the same formula and reverse the directions of the accelerating force and normal force, so it reflects a UA environment...you end up with the object being accelerated up the incline...not down.
Let me know if you want me to repost the explanations.
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Now imagine you accelerate the inclines plane upwards. The plane now exerts a force upwards on the ball. So the ball is pushing down on the plane. But because the plane is inclined a part of that force acts down the slope, so it moves (assuming that force is greater than the friction force). No?
No. I explained this is in an earlier post. The force the object exerts on the plane is cancelled out by the perpendicular force of the accelerating force. The only force left to accelerate the object is the force parallel to the incline, and it will accelerate the object in the direction of the force.
I have already showed the calculations using the standard formula for determining the force on an object on an incline in a gravity environment. If you use the same formula and reverse the directions of the accelerating force and normal force, so it reflects a UA environment...you end up with the object being accelerated up the incline...not down.
Let me know if you want me to repost the explanations.
Your calculation does not convert the excess force in to a tangential force to make the object rotate, it is just a generalization. In either case if the friction is too high, the object will not move relative to the coordinates of the slope, but if the friction is low enough the object will begin to rotate. If the slope is accelerating upwards, the rotating objects coordinates relative to the slope will translate from it's apex or top down to it's base. If it is gravity... it will do the same.
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Your calculation does not convert the excess force in to a tangential force to make the object rotate, it is just a generalization. In either case if the friction is too high, the object will not move relative to the coordinates of the slope, but if the friction is low enough the object will begin to rotate. If the slope is accelerating upwards, the rotating objects coordinates relative to the slope will translate from it's apex or top down to it's base. If it is gravity... it will do the same.
I don't know where you are getting "rolling" from, as I never specified the object as round...but whatever. Perhaps you can provide the formula and calculations that would demonstrate that that a ball on an incline that is being accelerated up , would actually roll down the incline.
That is the original question I asked.
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You know how to do the math, you don't know how to interpret Newtonian Mechanics. It's that simple. You did the math up above, but reached an improper conclusion because you don't understand how to analyze the system. If you interpret the plane as at rest, then it looks like the object slides down the hill, if you interpret the object as at rest, then it looks like the plane rises upwards.
Sorry about misreading the original problem though. If friction was ignored, then we are just looking at the inclined plane slipping past the object at rest.
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If you interpret the plane as at rest, then it looks like the object slides down the hill, if you interpret the object as at rest, then it looks like the plane rises upwards.
Under what circumstance would one ever interpret the object as being at rest? In neither scenario is the object just sitting motionless on the plane (assuming the angle is sufficient).
In both scenarios, the plane would be at rest and the object is moving. The question is just whether it is up or down the incline.
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If you interpret the plane as at rest, then it looks like the object slides down the hill, if you interpret the object as at rest, then it looks like the plane rises upwards.
Under what circumstance would one ever interpret the object as being at rest? In neither scenario is the object just sitting motionless on the plane (assuming the angle is sufficient).
In both scenarios, the plane would be at rest and the object is moving. The question is just whether it is up or down the incline.
Im out. You have no understanding of simple Newtonian relativity and are trying to argue against the equivalence principle. Good luck to you.
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Im out. You have no understanding of simple Newtonian relativity and are trying to argue against the equivalence principle. Good luck to you.
LOL, I understand enough of Newtonian relativity to know that if you are ever able to interpret something as being accelerated up...the equivalence principle isn't it play.
Its sort of the whole point of EP that you can't tell if something is being accelerated up or down. You can't have it both ways.
I also understand EP enough to know that it doesn't mean "that every gravitational field (e.g. , the one associated with the Earth) can be produced by acceleration of the coordinate system. It only asserts that the qualities of physical space, as they present themselves from an accelerated coordinate system, represent a special case of the gravitational field."
But yet people want to just apply it willynilly to any situation that suits them without explaining why or how it would apply in any given situation. It this situation, it specifically does not apply to objects on an incline. EP only applies to free falling objects. Objects on a inclined plane are not free falling.
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Its sort of the whole point of EP that you can't tell if something is being accelerated up or down. You can't have it both ways.
Hmm. I think the point of it is if you're in a lift and feel a force on your feet - as in, you have weight, weight is a force - you can't tell whether you are stationary and there is a force acting downwards or whether you are in a weightless environment and the lift is accelerating upwards
http://www.einstein-online.info/spotlights/equivalence_principle.html
If there is a force acting downwards because of gravity then this is how the forces work (simplifying, ignoring friction)
(https://i.ibb.co/vq0yd4q/gravity.jpg) (https://imgbb.com/)
That diagram is exactly the same if the force is caused by an upwards acceleration rather than a gravitational field.
You are not getting any support here from FE or RE people - when everyone is telling you that you're wrong then it might be worth considering whether you are.
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Objects on a inclined plane are not free falling.
How so?
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This person is an embarrassment to the scientific community.
Sorry dude/duchess but seriously why can't you grasp the simplest concepts in physics?
Seriously, if you are not schooled in the physical sciences, why come here and expound concepts just a flawed as the FE?
Sorry to be so blunt, but you have no more understanding of inclined planes under acceleration than you do of bubble levels under the same conditions.
I appreciate your position, but you seriously need a tutor or you need to do a lot more study before publicly humiliating yourself.
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That diagram is exactly the same if the force is caused by an upwards acceleration rather than a gravitational field.
Not exactly, the directions of the accelerating and normal forces would be reversed, but otherwise it would be the same. The calculations for determining the amount of force is exactly the same as well. I pointed that out earlier. The difference is that with the gravity calculations, the result is X amount of force pulling the object down an with UA, it is X amount of force pushing something up.
From an earlier post
Net Gravitational force 10kg @ 20 ⁰
Fnorm = 10.000 * 9.810 * cos(20) = 92.184N
F⊥= 10.000 * 9.810 * cos(20) = 92.184N
F// = 0.000 * 9.810 * sin(20) = 33.552N
The normal and perpendicular forces cancel each other out, so the net gravitational force is 33.552N. The net UA force would be the same, but in the opposite direction. How does that account for being accelerated downhill?
Net Gravitational force 10kg @ 30 ⁰
Fnorm = 10.000 * 9.810 * cos(30) = 84.957N
F⊥= 10.000 * 9.810 * cos(30) = 84.957N
F// = 10.000 * 9.810 * sin(30) = 49.050N
The normal and perpendicular forces cancel each other out, so the net gravitational force is 49.050N...same question as above.
Interesting observation…the net gravitational force increases as the angle increases. It’s almost as if the magnitude of the net gravitational forces on something change in response to how level it is.
The accelerating force is proportionally divided between the perpendicular and parallel, the perpendicular and normal forces cancel each other out, leaving only the parallel force to accelerate the object. If that accelerating force is UA, then the object will be accelerated up, if you use the same formula.
Acceleration is produced by a net force on an object and is directly proportional to the magnitude of the force, in the same direction as the force, and is inversely proportional to the mass of the object.
Acceleration = Force/mass (a = F/m)
http://www.csun.edu/~psk17793/S9CP/S9%20Acceleration.htm
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Acceleration is produced by a net force on an object and is directly proportional to the magnitude of the force, in the same direction as the force, and is inversely proportional to the mass of the object.
Acceleration = Force/mass (a = F/m)
Indeed. But, and this is the point you are repeatedly failing to understand, the object pushes DOWN on the inclined plane BECAUSE (under UA) the plane pushes UPWARDS on the object.
Newton's third law.
https://www.physicsclassroom.com/class/newtlaws/Lesson-4/Newton-s-Third-Law
The only difference under a gravitational field is that gravity causes the ball to push down on the plane, that causes the plane to push back up on the ball.
The cause of the force is different but the action and reaction forces are equivalent. That is the entire premise of the equivalence principle.
In either case the object pushes down on the plane so it goes down the slope, assuming the force down the incline is greater than gravity acting up it.
You ARE wrong about this, you just don't understand all this as well as you think you do. It's worth noting that literally everyone - FE and RE, including Einstein - is telling you than you're wrong.
So...you know, it's probably you, not everyone else.
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How so?
Free fall occurs whenever an object is acted upon by gravity alone.
https://physics.info/falling/
An object on an incline would be affected by both friction and normal force. An object in free fall cannot be supported because free fall implies weightlessness. When an object is supported, normal force creates the sensation of weight. The Equivalence Principle only applies to unsupported, free falling objects.
Free Fall- the term given to the motion of an unsupported object under the infulence of gravity
https://www.quia.com/jg/2434543list.html
The equivalence principle tells us that the "force" of gravity is the same as the pseudo-force effecting unsupported bodies in an accelerated frame of reference, and it is regarded as central to GR
https://www.researchgate.net/post/What_is_the_relationship_between_the_equivalence_principle_and_general_covariance_in_GR
The last thing we have to consider in our experiment is that a ball rolling down an inclined plane is not in free-fall. The inclined plane exerts some force on the ball
http://www.bu.edu/astronomy/files/2014/02/Gravity-New2014.pdf
“At the same location all unsupported objects fall towards the center of the earth at the same constant acceleration”
https://web2.ph.utexas.edu/~coker2/index.files/freefall.htm
Einstein's general theory of relativity, announced in 1915, uses the principle of equivalence to explain the force of gravity. There are two logically equivalent statements of this principle
First, consider an enclosed room on the Earth. In it, one feels a downward gravitational force. This force is what we call weight; it causes unsupported objects to accelerate downward at a rate of 32 ft/s2 (9.8 m/s2). Now imagine an identical room located in space, far from any masses. There will be no gravitational forces in the room, but if the room is accelerated "upward" (in the direction of its ceiling) at 9.8 m/s2—say, by a rocket attacked to its base—then unsupported objects in the room will accelerate toward its floor[/bold]at rate of 9.8 m/s2, and a person standing in the room will feel normal Earth weight.
https://science.jrank.org/pages/5790/Relativity-General.html
“…for example, there is allegedly no way to distinguish the assertion that all unsupported objects of a certain class fall to the ground from the assertion that [bold]unsupported objects [/bold]in that class near the earth are attracted by the earth according to Galileo’s law of free fall.”
https://books.google.com/books?id=lXda41Q0FgIC&pg=PA266&lpg=PA266&dq=%22for+example,+there+is+allegedly+no+way+to+distinguish+the+assertion%22&source=bl&ots=VN9nLq2Xl9&sig=ACfU3U1qA5EMZly8XjeP97dtf44MOPLR_w&hl=en&sa=X&ved=2ahUKEwicsIWEj7XlAhUGZd8KHdu5CTcQ6AEwAHoECAAQAg#v=onepage&q=%22for%20example%2C%20there%20is%20allegedly%20no%20way%20to%20distinguish%20the%20assertion%22&f=false
5.15 Freely Falling Bodies
We know from everyday experience that unsupported objects located at some height tend to fall towards the ground.
https://books.google.com/books?id=wjs_DAAAQBAJ&pg=SA5-PA31&lpg=SA5-PA31&dq=%22freely+falling%22++%22unsupported+objects%22&source=bl&ots=0rT2NDwxSc&sig=ACfU3U2wS03WU6DKmMRYIGCTGR_bOkf_Yw&hl=en&sa=X&ved=2ahUKEwi_3eWpjLXlAhUlmeAKHXdTBrwQ6AEwCXoECAcQAg#v=onepage&q=%22freely%20falling%22%20%20%22unsupported%20objects%22&f=false
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Indeed. But, and this is the point you are repeatedly failing to understand, the object pushes DOWN on the inclined plane BECAUSE (under UA) the plane pushes UPWARDS on the object. Newton's third law
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No, what you are failing to understand is the UPWARDS force that would exist with gravity and downwards force that would exist with UA which is called the Normal Force, is cancelled out by the perpendicular force. Resulting in the effect of no upwards force at all.
The normal force is the support force exerted upon an object that is in contact with another stable object. For example, if a book is resting upon a surface, then the surface is exerting an upward force upon the book in order to support the weight of the book.
https://www.physicsclassroom.com/Class/newtlaws/U2L2b.cfm#norm
In a gravity environment, the normal force will produce an upward force to balance the downward effect of gravity. In UA, it would be the opposite. The normal force would produce a downward force to balance the upward effect of UA.
However...
The vertical forces (perpendicular to the incline) (which would be gravity or UA) cancel out, because the normal force equals the perpendicular component of the weight force; thus, we are only looking at forces parallel to the incline.
https://socratic.org/questions/an-object-with-a-mass-of-5-kg-is-on-a-plane-with-an-incline-of-pi-8-if-the-objec-3
IOW, the net force between the object and the plane is zero. The plane is pushing on the object with the same force as the object is pushing on the plane so the net result is zero force. There is no force between the object and the plane.
Newton's first law states that an object that remains in uniform motion will remain in uniform motion unless it is acted upon by an external force. This also includes that an object at rest will remain at rest unless it is acted upon by an external force. When more than one force acts upon an object, the vector sum of these forces is the resultant force.
https://en.wikibooks.org/wiki/Statics/Newton%27s_Laws_and_Equilibrium
Since the normal force and the perpendicular force cancel each other out, the resultant force is the parallel force only.
The perpendicular component of the force of gravity is directed opposite the normal force and as such balances the normal force. The parallel component of the force of gravity is not balanced by any other force. This object will subsequently accelerate down the inclined plane due to the presence of an unbalanced force.[bold] It is the parallel component of the force of gravity that causes this acceleration.[/bold] The parallel component of the force of gravity is the net force
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If it is the parallel component of gravity which accelerates an object down, the parallel component of UA would accelerate it up. There is no other forces (assuming no friction or applied force) working on the object that could cause it to accelerate down.
https://www.physicsclassroom.com/class/vectors/Lesson-3/Inclined-Planes