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#20 by Aurelian on 29 Nov, 2019 08:43
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I think that common understanding of inertia presented in textbooks include object's ability to stay in uniform motion when no external forces act on it. A good and concise summary of inertia's definition is on Wikipedia:By definition, inertia defines the capacity of an object to move perpetually without using external forces. What is the mechanism maintaining such perpetual motion? Can we replicate it? The answers to these questions would help to improve our understanding of motion and to build new technologies for space and other domains.
Congratulations on your first post and welcome to the forum.
A new view on inertia is presented in the paper linked below this text. The paper describes an experiment which provides clues on how inertia works. It includes also simple math which explains the operation of the device described in the experiment. The results indicate that inertia of an object is an emergent phenomenon which arises from the variable inertia of the constituents of the object.
Does this paper describe new physics? Read the paper and decide for yourself.
Here is the paper: the mechanism of inertia.
No!
Inertia is a force that resists acceleration of an object of mass... :-)
That includes its ability to move uniformly on a straight line when undisturbed by external forces.
No! Inertial force is only present when acceleration force acts on a body of mass... :-)
Inertial force is zero if an object moves with constant linear velocity... :-)
https://en.m.wikipedia.org/wiki/Inertia.
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#21 by MathewOrman on 29 Nov, 2019 08:48
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I think that common understanding of inertia presented in textbooks include object's ability to stay in uniform motion when no external forces act on it. A good and concise summary of inertia's definition is on Wikipedia:By definition, inertia defines the capacity of an object to move perpetually without using external forces. What is the mechanism maintaining such perpetual motion? Can we replicate it? The answers to these questions would help to improve our understanding of motion and to build new technologies for space and other domains.
Congratulations on your first post and welcome to the forum.
A new view on inertia is presented in the paper linked below this text. The paper describes an experiment which provides clues on how inertia works. It includes also simple math which explains the operation of the device described in the experiment. The results indicate that inertia of an object is an emergent phenomenon which arises from the variable inertia of the constituents of the object.
Does this paper describe new physics? Read the paper and decide for yourself.
Here is the paper: the mechanism of inertia.
No!
Inertia is a force that resists acceleration of an object of mass... :-)
That includes its ability to move uniformly on a straight line when undisturbed by external forces.
No! Inertial force is only present when acceleration force acts on a body of mass... :-)
Inertial force is zero if an object moves with constant linear velocity... :-)
https://en.m.wikipedia.org/wiki/Inertia.
Uniform motion is relative so your assumed property as ability of perpetual motion is useless... :-)
How do you know that object is moving in space?
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#22 by JohnFornaro on 29 Nov, 2019 13:56
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By definition, inertia defines the capacity of an object to move perpetually without using external forces.
Didn't Newton say something about a body in motion? Briefly, what's new in this link? That we get to ignore the force that put the body in motion in the first place? -
#23 by JohnFornaro on 29 Nov, 2019 13:57
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The paper starts by mischaracterizing Newton's law of inertia...
I knew Newton had something to do with this! -
#24 by JohnFornaro on 29 Nov, 2019 14:41
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From the paper:
"Inertia is emerging at macroscopic level from the variable inertia of the microscopic particles which compose an object."
"Variable" inertia? Push heavy, pull light? I've only read the first sentence of meberbs' post after your OP.
"The first law of motion is a definition of inertia that does not provide a mechanism of inertia to explain how an object keeps moving when no force acts on it." You will never be able to come up with a definition of inertia until you understand the well known forces acting in the universe at this very moment. "Since inertia is continuous motion in lack of external forces..." Repeating the same misguided notion does not make it true.
"We assume that all weights start rotating in the same time and with the same constant speed..." No. You cannot make this assumption. You have to apply a force to accelerate the weights from rest to the constant speed.
"If we split [the] system along the OO' axis, disconnecting the devices from each other at the moment when the weights pass through their starting position, then the system will lose its equilibrium..." You have to be introducing a new force, either mechanical or electromagnetic, to the system by disconnecting the devices and that disconnection takes place over a finite time interval. It doesn't look like "Algodoo" correctly accomodates the reality of your initial setup.
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#25 by JohnFornaro on 29 Nov, 2019 14:42
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NSF is not the place to get purported science papers peer reviewed.
Meberbs is performing a welcome community service. -
#26 by JohnFornaro on 29 Nov, 2019 14:59
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It accelerates without any external force acting on it. Note, that gravity and air resistance were disabled in Algodoo scene.
You cannot accelerate anything without applying a force to it. Algodfoo appears to be a toy in this regard.Quote from: AurelianThe object starts by itself to accelerate.
The only reason you can say that, I think, is because it's a free country. You have not yet properly accounted for the forces required to bring the spinning discs up to speed. -
#27 by JohnFornaro on 29 Nov, 2019 15:04
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I have never disagreed with the math in the paper...
Here, if ya don't mind, I could use a bit of a math lesson from you. I substituted Aurelian's Csub1 of equation (3) back into equation (2) and couldn't understand the result. -
#28 by Aurelian on 29 Nov, 2019 15:40
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It accelerates without any external force acting on it. Note, that gravity and air resistance were disabled in Algodoo scene.
You cannot accelerate anything without applying a force to it. Algodfoo appears to be a toy in this regard.Quote from: AurelianThe object starts by itself to accelerate.
The only reason you can say that, I think, is because it's a free country. You have not yet properly accounted for the forces required to bring the spinning discs up to speed.
The first example in the paper talks about the devices connected back to back. The method of putting the discs in rotation was ignored since either method is used - electric, magnetic, someone pushing the levers - it would create equal and opposing forces on each devices which will cancel each other out. Once the discs are up to speed, after the devices are disconnected, they will move away from each other under the influence of the y-components of the centrifugal forces.
The equation of speed shows that periodically the device will have speed equal to zero in the chosen reference system. Right after those moments the device accelerats without any external force acting on them, but only under the influence of their internal centrifugal forces.
In the Algodoo simulation the spinning discs are put in motion by motors set in the pivoting points.
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#29 by Aurelian on 29 Nov, 2019 15:44
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I have never disagreed with the math in the paper...
Here, I ya don't mind, I could use a bit of a math lesson from you. I substituted Aurelian's Csub1 of equation (3) back into equation (2) and couldn't understand the result.
I checked again. Substituting C1 in equation 2 leads to equation 4. Let me know what needs to be clarified.
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#30 by Aurelian on 29 Nov, 2019 15:51
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The paper starts by mischaracterizing Newton's law of inertia...
I knew Newton had something to do with this!
I and meberbs clarified this statement which was related to meaning of the "rectilinear" word in my paper.
The general disagreement from several users with my paper is over the interpretation of the experiment and math. That is mainly related to the role of the center of mass in the interpretation of the results.
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#31 by meberbs on 29 Nov, 2019 18:02
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As I tried to make clear before, I didn't thoroughly check the details of every equation, and it looks like there is a mistake in equation 2 that I had missed. This is clear when you look at the units, because you end up with acceleration rather than velocity. A factor of 1 over omega should have appeared when taking the integral. I haven't checked the rest of that term to make sure it accounts for everything correctly, all I had checked before was that the general form was correct.I have never disagreed with the math in the paper...
Here, if ya don't mind, I could use a bit of a math lesson from you. I substituted Aurelian's Csub1 of equation (3) back into equation (2) and couldn't understand the result.
The result is as expected given the initial conditions of starting with the boxes next to each other and the masses already in motion. If you want to track the buildup of momentum through forces between the boxes you can do so. A simple version is to start with the spinning masses at rest and 90 degrees behind the release point in the diagram. vertical components of forces cancel out with the 2nd ball in each box. As the balls are accelerated up to speed, the reaction force the motor in the box experiences from doing so pushes the boxes together. The horizontal component of the centrifugal force interaction has the same effect. In this way, the boxes continue to apply forces to each other, exchanging momentum, but they remain in contact since the momentum all ends up in the spinning masses. At the release point, the balls are now at speed and the motors stop applying force (friction is ignored) the horizontal component from the centrifugal force switches directions at that point, so past there, the balls transfer their outward momentum to their respective box, and the boxes move apart. Each system then has its center of mass move with constant velocity from that point on since there are no more forces between the boxes. The individual components of the system have some oscillation due to the balls spinning, but that is of course irrelevant.The general disagreement from several users with my paper is over the interpretation of the experiment and math. That is mainly related to the role of the center of mass in the interpretation of the results.
It is not so much a disagreement, as you asserting that a result derived from Newton's laws is somehow non-Newtonian. There is no question what Newton's laws mean. The description for the motion above and all of those steps are exactly what Newtonian mechanics predicts. There are forces between the boxes and the balls and therefore the motion of those individual objects acts as if there are forces acting on them, since there are, making them consistent with Newton's laws. If you define your system to instead be the combination of the box and the balls, then if you track the center of mass of that, you will see it moving with constant velocity. At no point do Newton's laws claim that the outside shell of a box will not move regardless of what objects inside do. Newton's laws in fact say the opposite. If an object inside the box moves, applying a force to the box, it makes the box move in the opposite direction.
There is also the matter of the talk about "quantization" in the paper, when nothing discussed has anything to do with quantization at all. -
#32 by Aurelian on 29 Nov, 2019 18:38
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Yes, the 1 over omega should be there (lost it from my paper notes). However, the equation of the speed remains sinusoidal; just the amplitude changes. Therefore the device still moves sinusoidally.
As I tried to make clear before, I didn't thoroughly check the details of every equation, and it looks like there is a mistake in equation 2 that I had missed. This is clear when you look at the units, because you end up with acceleration rather than velocity. A factor of 1 over omega should have appeared when taking the integral. I haven't checked the rest of that term to make sure it accounts for everything correctly, all I had checked before was that the general form was correct.I have never disagreed with the math in the paper...
Here, if ya don't mind, I could use a bit of a math lesson from you. I substituted Aurelian's Csub1 of equation (3) back into equation (2) and couldn't understand the result.
As I said previously, if we consider the center of mass or point like objects, the device moves uniformly on straight line. But the proposed device moves sinusoidally; its speed is not constant. -
#33 by Nick on 29 Nov, 2019 18:40
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The general disagreement from several users with my paper is over the interpretation of the experiment and math. That is mainly related to the role of the center of mass in the interpretation of the results.
I have a slightly more fundamental problem.
Your Figure 2 is a diagram of your device at rest (but with the arms and masses spinning). More precisely, it is a diagram of the device in the specific inertial frame of reference in which the centre of mass of the device is at rest. You then show the four rotating masses each being acted upon by a centrifugal force F, the four F's being at 90 degrees to each other. You show no other forces.
Centrifugal force does not exist in an inertial reference frame. It is an artefact which appears when one describes motion in a rotating frame of reference. The common example is the perceived tendency for a person to be flung off a playground roundabout when it is spinning. Although that force appears "real" to the person on the roundabout, in the inertial frame of reference of the playground itself, it does not exist. If the person lets go of the roundabout, no force throws them off. They simply continue in a straight line along the tangent to the edge of the roundabout at the time of release. The roundabout continues to rotate, the planks and bars of which it is made being held in circular motion by tensional forces in its structure.
Returning to your example, in the frame of the device, each of your masses, m, have a centripetal force F acting on them at 180 degrees to the force F you show. That is balanced by an equal and opposite force F acting on the arm applied by its axle. The in turn is balanced by a force from the plate in which the axle turns and a force is applied in reaction to the plate.
Because of the symmetry of the initial conditions when spins were set in motion, the x-components of these forces from each pair of mass/arm/axle arrangements on each plate will balance out, and each plate will be left subject to a force along the y-axis. with a sinusoidal variation in amplitude.
However, the further symmetry with the other plate generates an equal and opposite force on its plate. As the two plates are attached, the boundary between them will be in tension or compression depending on where the masses are in their rotations, but the combined system will remain at rest.
If the attachment between the plates is severed, then as soon as the force at the boundary becomes tensive, the two plates will move apart. The centre of mass of the entire two-plate, four-mass system will however remain stationary.
As the masses continue to spin, the plates will undergo an oscillatory motion in opposition to the rotating masses. I am inclined to believe that the plates will return to contact with each other periodically, but I freely admit that the exact motion has now become complex, as the masses and the plates trade rotational and kinetic energy.
However, this is a straightforward piece of classical mechanics - someone more current in the subject than I and with more time on their hands may care to do the analysis.
But to return to my original point - centrifugal forces do not exist in inertial frames. Centripetal forces do, and in any analysis of any mechanical system it is key to understand all the actions and reactions at play between all the components. It is also key to ensure that your analysis contains only forces that exist in the frame of reference you are working in. Many people have neglected these constraints and used rotating masses to allegedly create anti-gravity and perpetual motion machines. None have worked.
Sir Isaac still remains supreme! (Well, in the macroscopic and low velocity realms anyway. We turn to the Mighty Albert and his contemporaries in other contexts...
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#34 by meberbs on 29 Nov, 2019 18:49
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As I said previously, if we consider the center of mass or point like objects, the device moves uniformly on straight line. But the proposed device moves sinusoidally; its speed is not constant.
The question remains: so what? Newton's laws apply for center of mass or for rigid objects where forces are applied through the center of mass. (you can also get sinusoidal results by simply spinning a rigid object and tracking the position of the end points.)
This is not a new or enlightening result, as it has been known for hundreds of years. Your paper takes this and jumps to other completely unsupported conclusions, which are all negated by the simple fat that the described motion is exactly what Newton's laws predict. -
#35 by Aurelian on 29 Nov, 2019 18:51
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Many people have neglected these constraints and used rotating masses to allegedly create anti-gravity and perpetual motion machines. None have worked.
I do not claim the device is anti-gravity or perpetuum mobile.
It's analysis is much simpler if you consider one device with two arms connected to pivoting points, but without any spinning discs connected to them. If someone from the ground throws into the device two discs which will be connected magnetically (or somehow else) to the arms of the device, then the device should start moving to conserve momentum. But it will start not moving uniformly, but gradually accelerate as the spinning discs begin rotating on the arms of the device.
[Zubenelgenubi fixed quote] -
#36 by Aurelian on 29 Nov, 2019 18:55
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That rigid spinning object will not have periodic full stops (zero speed) as the proposed device nor variable kinetic energy.As I said previously, if we consider the center of mass or point like objects, the device moves uniformly on straight line. But the proposed device moves sinusoidally; its speed is not constant.
The question remains: so what? Newton's laws apply for center of mass or for rigid objects where forces are applied through the center of mass. (you can also get sinusoidal results by simply spinning a rigid object and tracking the position of the end points.)
This is not a new or enlightening result, as it has been known for hundreds of years. Your paper takes this and jumps to other completely unsupported conclusions, which are all negated by the simple fat that the described motion is exactly what Newton's laws predict.
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#37 by meberbs on 29 Nov, 2019 19:10
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If the center of mass is also moving at just the right velocity (i.e. you pick just the right frame to do the calculations), then there will be points where it balances out and tracking a specific dot on that object will show the dot is instantaneously stationary, as the momentum is located in other parts of the object.
That rigid spinning object will not have periodic full stops (zero speed) as the proposed device nor variable kinetic energy.As I said previously, if we consider the center of mass or point like objects, the device moves uniformly on straight line. But the proposed device moves sinusoidally; its speed is not constant.
The question remains: so what? Newton's laws apply for center of mass or for rigid objects where forces are applied through the center of mass. (you can also get sinusoidal results by simply spinning a rigid object and tracking the position of the end points.)
This is not a new or enlightening result, as it has been known for hundreds of years. Your paper takes this and jumps to other completely unsupported conclusions, which are all negated by the simple fat that the described motion is exactly what Newton's laws predict.
Your device also has constant kinetic energy. You only get different results if you look at the box while ignoring that there is continuous energy and momentum exchange between the box and the balls. But, it should be clear that ignoring that interaction is wrong. -
#38 by Aurelian on 29 Nov, 2019 19:51
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Tracking the imaginary massless point called center of mass for a rigid object does not produce the same effects as with the device proposed in my paper.
If the center of mass is also moving at just the right velocity (i.e. you pick just the right frame to do the calculations), then there will be points where it balances out and tracking a specific dot on that object will show the dot is instantaneously stationary, as the momentum is located in other parts of the object.
That rigid spinning object will not have periodic full stops (zero speed) as the proposed device nor variable kinetic energy.As I said previously, if we consider the center of mass or point like objects, the device moves uniformly on straight line. But the proposed device moves sinusoidally; its speed is not constant.
The question remains: so what? Newton's laws apply for center of mass or for rigid objects where forces are applied through the center of mass. (you can also get sinusoidal results by simply spinning a rigid object and tracking the position of the end points.)
This is not a new or enlightening result, as it has been known for hundreds of years. Your paper takes this and jumps to other completely unsupported conclusions, which are all negated by the simple fat that the described motion is exactly what Newton's laws predict.
Your device also has constant kinetic energy. You only get different results if you look at the box while ignoring that there is continuous energy and momentum exchange between the box and the balls. But, it should be clear that ignoring that interaction is wrong.
For example, when the device stops, it really stops for external users (let's say the people on ground - the reference system). They could just jump on it (if they are quick enough...). Or better example, if a train uses such propulsion it could stop at the stations by just hooking its frame to the track (mechanically, magnetically etc.) whenever its speed is zero. It's propellers will still spin, but the train is at rest. There are other examples and applications of sinusoidal inertia.
The center of mass is an imaginary point. It is a good to model motion for point like masses and rigid objects, which have no rotating entities. The device that I described provides an example for which the center of mass model is totally irrelevant.
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#39 by ChrisWilson68 on 30 Nov, 2019 00:52
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Tracking the imaginary massless point called center of mass for a rigid object does not produce the same effects as with the device proposed in my paper.
Calling a point "imaginary" or "massless" isn't really meaningful. Points are abstractions. No point is more or less imaginary than any other point. And points never have mass. That's not part of what a point is. A point is a geometric concept.
You seem to just be repeating that the center of mass doesn't move as the outside box of your proposed device. Again, as others have said, there's nothing new or surprising here. It's a pretty trivial result that such a device can be built.For example, when the device stops, it really stops for external users (let's say the people on ground - the reference system). They could just jump on it (if they are quick enough...). Or better example, if a train uses such propulsion it could stop at the stations by just hooking its frame to the track (mechanically, magnetically etc.) whenever its speed is zero. It's propellers will still spin, but the train is at rest.
The amount of time a part of the device would be at rest without losing the overall momentum of the system would be tiny if the speed of the entire system was anything practical. So such a train would be completely impractical.There are other examples and applications of sinusoidal inertia.
The term "sinusoidal inertia" is not appropriate for what you are talking about. It's not sinusoidal inertia at all. It's plain old inertia with some rotation causing sinusoidal motion of some parts.
If you think there are other uses for this, please specify them and we can discuss the specific ideas.The center of mass is an imaginary point. It is a good to model motion for point like masses and rigid objects, which have no rotating entities. The device that I described provides an example for which the center of mass model is totally irrelevant.
It's not totally irrelevant. The concept of the center of mass is useful for many purposes for your device, including reasoning about the total momentum and energy of the system.
Anyway, it's clear you're not claiming anything having to do with new physics any more.
Could we close this thread in the "New Physics" section and if you have ideas for practical uses of your device or something like it, could you create new threads for these ideas in the "Advanced Concepts" section?
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