So I looked at the "paper" and it doesn't need meberbs, though his reaction would be a joy to read. It's just the usual confusion between changing the center of mass of a system and the rocket equation. There was another of these just a few weeks back, same fallacy.

Turning the screw causes the center mass to move in a straight line, which changes the center of mass of the system, but that's all. It doesn't add or subtract momentum from the system unless the mass is ejected. As long as it's firmly attached to the system, there's no overall momentum change.

You read the paper but you understood nothing.

Seriously though, both setups work the same way. There is no induced force. Helical vs. collinear entanglement is a meaningless fictitious concept.

Consequently, any change in momentum of mass mA results in the non-zero change in momentum of system as a whole.

Since mass mA is physically part of the system and is never released, its momentum is part of the momentum of the entire system.

The paper ignores the corresponding momentum change (angular and linear) of the rest of the device that compensates for the motion of mA.

*snip*QuoteSince mass mA is physically part of the system and is never released, its momentum is part of the momentum of the entire system.Your statement addresses the case where Newton's 3rd law holds. You cannot use the same argument when Newton's 3rd law does not hold. In Fig.2. Upper, Newton's 3rd law breaks that means the induced internal reaction force has the same direction with the induced internal action force that corresponds to a different momentum conservation of what we knew up to now. In other words, Newton's 3rd law should always agree with the momentum conservation.Quote The paper ignores the corresponding momentum change (angular and linear) of the rest of the device that compensates for the motion of mA.See eq.21 to 26 for collinear forces (Fig.2. Lower), where there is no change in system's momentum (as you mentioned above). The total sum of the collinear forces is zero therefore no system motion may occur.See eq.27 to 30 for induced forces (Fig.2. Lower), where there is a change in system's momentum (it does not conform with Newton's 3rd law). Here the total sum of the induced internal forces are not zero, which is the reason of system's motion.

Where you are going wrong is assuming you have broken Newton's 3rd law, when you have not. The mechanisms as shown in Fig. 2 can move the center of gravity and cause the mechanism to rotate, but that movement does not violate conservation of momentum.

You've obfuscated this error with a lot of words and math, but it's still an error.I agree with laszlo that mberbs can point out where you've gone wrong with greater detail.

Newton's laws are sound.When you have a high mass ir high speed they have to be adjusted to compensate.The twi together are perfect.

QuoteWhere you are going wrong is assuming you have broken Newton's 3rd law, when you have not. The mechanisms as shown in Fig. 2 can move the center of gravity and cause the mechanism to rotate, but that movement does not violate conservation of momentum.I presented my arguments but you and laszlo are stuck in Newton's 3rd law without having examined/understood what is different with Fig.2. Upper. The Thought Experiment I presented above follows exactly the mathematical arguments of the theory as also about the construction (Fig.2. Upper) itself. If you are interested to debunk the theory, I will give you a hint (1): attempt to debunk the claims of the Thought Experiment. Or hint (2): Suspend a linear actuator by a thread and power it.QuoteYou've obfuscated this error with a lot of words and math, but it's still an error.I agree with laszlo that mberbs can point out where you've gone wrong with greater detail.Nothing is obfuscated. I will be happy to point me (you or mberbs or whoever) where I am wrong (up to now none did it). That way I will stop losing my time (and yours).

meberbs will say all this much better.

The following paper assumes that Newton's 3rd law is incomplete and proposes a very simple mechanical construction (linear actuator) to prove it.

2.The internal parts of system A are linearly entangled (through a straight metallic thick thread) with each other

6.Isolated system B is a real linear actuator (nothing to do with collinear forces). See Fig.2. Upper

7.The internal parts of system B are helically entangled (through a straight metallic leadscrew) with each other

8.A clockwise rotation of the screw, creates a counterclockwise (conservation of angular momentum) induced internal action force9.Because of 8, the internal part starts to accelerate to the right10.Because of 8, it is allowed only unidirectional induced forces to be developed

11.Because of 10 the induced internal reaction force will be also counterclockwise

There are two ways to falsify the above claims (and the theory as a whole):1.Find what is wrong from eq.1 to eq.20

A Final NoteNewton's third law of motion would be the cornerstone of physics were it not for certain experimental results that demonstrate a conflict with conservation of momentum under certain special circumstances. The breaking of action-reaction symmetry (Newton’s 3rd law) is a subject being addressed by various disciplines in physics as in statistical mechanics, optics and others. Indicative research on this subject can be found below (or see Paper References):

https://journals.aps.org/prx/abstract/10.1103/PhysRevX.5.011035 (Statistical Mechanics where Newton’s Third Law is Broken)

Of course, Newton’s third law holds for the complete “particles-plus-environment” system.

As you may see Newton's 3rd law has been already broken in other disciplines of physics (see first post or paper References) and it is very logical for one to conclude why it is not evident in classical mechanics?

Are Newton's laws of motion incomplete?

The paper assumes they are incomplete and uses the construction in Fig.2.Upper with the corresponding math to prove it.

Thank you for your hints. I did hint one, by pointing out the fallacies, but since it doesn't agree with the premise (newton's 3rd law is broken) it was ignored.

Hint 2, suspending a linear actuator by a thread has no connection whatsoever to the thought experiment because it's not an isolated system. Gravitation, air resistance, thread torsion, etc. all violate the thought experiment's premise of an isolated system.

Regarding figure 2, upper - it is identical with figure 2 lower except for the threaded drive, right? Do we at least agree on that? If so, there is no difference from a 3rd law point of view. If you "unwrap" the threaded rod to account for the mechanical advantage, upper becomes lower, just longer.

The angular momentum disappears, true, but that was already net zero even with the threaded rod. The framework and masses acquired exactly enough opposite angular momentum to cancel the momentum of the rotating threaded rod.

Here's something that may help you visualize it - in your truly isolated system, move the motor driving the rod from the end of the frame to the center of mass mA and work the equations again. See if there's any difference in the results when the moving mass spins the threaded rod instead of the fixed framework spinning it.

Quote from: Reactionless2020 on 07/26/2020 11:31 am2.The internal parts of system A are linearly entangled (through a straight metallic thick thread) with each other"linearly entangled" is a nonsense phrase. It is one of multiple such terms used in the paper to handwave into existence forces that don't exist that are simply contrary to conservation laws.