[Kryptid]

I am not sure what is your question,

It's here. The sentence that is underlined:

Just to make sure that you actually understand what conservation of momentum means (because it's far from clear that you do), take a look at this quote from "the Physics Classroom" website: https://www.physicsclassroom.com/class/momentum/Lesson-2/Momentum-Conservation-Principle

One of the most powerful laws in physics is the law of momentum conservation. The law of momentum conservation can be stated as follows.

For a collision occurring between object 1 and object 2 in an isolated system, the total momentum of the two objects before the collision is equal to the total momentum of the two objects after the collision. That is, the momentum lost by object 1 is equal to the momentum gained by object 2.

The above statement tells us that the total momentum of a collection of objects (a system) is conserved - that is, the total amount of momentum is a constant or unchanging value.

I bolded the important bit. Based on this, do you understand that conservation of momentum means that the total momentum of a closed system cannot change?

[Jaaanosik (OP)]

I am not sure what is your question,

It's here. The sentence that is underlined:

Just to make sure that you actually understand what conservation of momentum means (because it's far from clear that you do), take a look at this quote from "the Physics Classroom" website: https://www.physicsclassroom.com/class/momentum/Lesson-2/Momentum-Conservation-Principle

One of the most powerful laws in physics is the law of momentum conservation. The law of momentum conservation can be stated as follows.

For a collision occurring between object 1 and object 2 in an isolated system, the total momentum of the two objects before the collision is equal to the total momentum of the two objects after the collision. That is, the momentum lost by object 1 is equal to the momentum gained by object 2.

The above statement tells us that the total momentum of a collection of objects (a system) is conserved - that is, the total amount of momentum is a constant or unchanging value.

I bolded the important bit. Based on this, do you understand that conservation of momentum means that the total momentum of a closed system cannot change?

Yes, please, see the post #179 for the explanation,
Jano

[Kryptid]

Yes

Good. Now, the following things are true:

(1) The ship starts out with no momentum (angular or linear).
(2) The ship is a closed system (nothing is entering or leaving it).

Given that you have just agreed that a closed system must conserve momentum, we must conclude the total momentum of the ship at the end of stroke one must be equal to the total momentum of the ship before stroke one. Do you agree with this?

The cat burning potential energy is losing atoms, mass is getting out of the system.
The rotating cat is not a closed system.
Jano

Although this is true on a technical level, the cat is not receiving any angular momentum from the environment so it's a moot point.

What is causing the wobble of the CD players when they are ON and when they receive gentle external impulse?
Where is the action and counter-reaction coming from?

This is called gyroscopic precession. This video explains the physics behind it:

Nothing about it violates conservation of angular momentum.

The black ball is a closed system.
The dark blue wheel is a closed system.

The very moment that those two objects interact with each other, they cease to be closed systems. A closed system is one that does not interact with other systems.

The conclusion is that the internal subsystems can change their values, conversion from one momentum to another.
Even a conversion from linear to angular.

Not if Noether's theorem has anything to say about it.

[Jaaanosik (OP)]

The black ball is a closed system.
The dark blue wheel is a closed system.

The very moment that those two objects interact with each other, they cease to be closed systems. A closed system is one that does not interact with other systems.
...

The text book is clear, a close system does not change its momentum till there is an external impulse.
Where do you get your definition that "A closed system is one that does not interact with other systems"?
This is a little nuance or playing on words but very important.
It appears the only system that fits your definition is the whole Universe, if we assume there is nothing outside the Universe.
As mentioned above, the black ball is a closed system but it can change the momentum when it interacts with the wheel, the external impulse as per the textbook.
The wheel is a closed system, it is not moving, till there is an external impulse that is going to cause the rotation, as per the textbook,
Jano

[Kryptid]

Where do you get your definition that "A closed system is one that does not interact with other systems"?

I have to admit, I had not encountered the definition of closed system that you posted before. An isolated system is more what I was thinking.

In any case, the spaceship is not only a closed system, but also an isolated system (it doesn't utilize any external mechanisms. It tries to move using only its internal mechanisms). That being said, do you agree that its momentum must remain unchanged since it is an isolated system?

[Jaaanosik (OP)]

...
This is called gyroscopic precession. This video explains the physics behind it:

Nothing about it violates conservation of angular momentum.
...

If this was a simple gyro precession then the CD players body would not wobble.
It would keep some kind of rotation.
There are 3 gyros. That's the difference. Therefore there is a wobble, the potential well,
Jano

[Jaaanosik (OP)]

Where do you get your definition that "A closed system is one that does not interact with other systems"?

I have to admit, I had not encountered the definition of closed system that you posted before. An isolated system is more what I was thinking.

In any case, the spaceship is not only a closed system, but also an isolated system (it doesn't utilize any external mechanisms. It tries to move using only its internal mechanisms). That being said, do you agree that its momentum must remain unchanged since it is an isolated system?

We need to know where you got your definition.
As mentioned, the only system is the whole Universe based on your definition.
... and even that one is conditional that there is nothing outside the Universe,
Jano

[Kryptid]

If this was a simple gyro precession then the CD players body would not wobble.

Gyroscopic precession does cause a wobble. It's what causes a spinning top to wobble.

So how about answering my question?

We need to know where you got your definition.
As mentioned, the only system is the whole Universe based on your definition,
Jano

This is one such example: https://www.dictionary.com/browse/closed-system

[Jaaanosik (OP)]

If this was a simple gyro precession then the CD players body would not wobble.

Gyroscopic precession does cause a wobble. It's what causes a spinning top to wobble.

So how about answering my question?

We need to know where you got your definition.
As mentioned, the only system is the whole Universe based on your definition,
Jano

This is one such example: https://www.dictionary.com/browse/closed-system

Really???
A dictionary definition???
We need a better one.
What is your question?
Jano

[Kryptid]

Really???
A dictionary definition???

And what is your problem with dictionaries?

What is your question?

This:

In any case, the spaceship is not only a closed system, but also an isolated system (it doesn't utilize any external mechanisms. It tries to move using only its internal mechanisms). That being said, do you agree that its momentum must remain unchanged since it is an isolated system?

Remember, no momentum is entering or leaving the ship.

[Jaaanosik (OP)]

If this was a simple gyro precession then the CD players body would not wobble.

Gyroscopic precession does cause a wobble. It's what causes a spinning top to wobble.

So how about answering my question?

We need to know where you got your definition.
As mentioned, the only system is the whole Universe based on your definition,
Jano

This is one such example: https://www.dictionary.com/browse/closed-system

How is the gyro precession causing a wobble?
Is it in the youtube videos? Where the gravity is involved?
Do you have a single wheel precession in micro-gravity?
I don't think so: 

Jano

[Kryptid]

How is the gyro precession causing a wobble?

It's explained by Wikipedia here: https://en.wikipedia.org/wiki/Precession#Classical_(Newtonian)

Is it in the youtube videos? Where the gravity is involved?
Do you have a single wheel precession in micro-gravity?

Gravity is not involved.

Now answer my question.

[Jaaanosik (OP)]

Really???
A dictionary definition???

And what is your problem with dictionaries?

What is your question?

This:

In any case, the spaceship is not only a closed system, but also an isolated system (it doesn't utilize any external mechanisms. It tries to move using only its internal mechanisms). That being said, do you agree that its momentum must remain unchanged since it is an isolated system?

Remember, no momentum is entering or leaving the ship.

No momentum is entering or leaving the ship?
I was saying the ship is collecting hydrogen from the space.
Still this is not relevant because the question is whether a system can generate something that resembles external momentum from within the system.
What momentum entered or left the cat when it rotated half a turn?
Jano

[Jaaanosik (OP)]

How is the gyro precession causing a wobble?

It's explained by Wikipedia here: https://en.wikipedia.org/wiki/Precession#Classical_(Newtonian)

Is it in the youtube videos? Where the gravity is involved?
Do you have a single wheel precession in micro-gravity?

Gravity is not involved.

Now answer my question.

There is no wobble from a single gyro in micro-gravity, check the video.

Please, what is your question?
There were many posts, I do not know what question you are asking,
Jano


Edit: this one?
That being said, do you agree that its momentum must remain unchanged since it is an isolated system?

There is no answer till we settle the closed system definition.

Edit2:
The answer is in pointing out how the cat rotated without external momentum.

[Kryptid]

There is no wobble from a single gyro in micro-gravity, check the video.

I can see it wobble. The wobble is just very small.

Please, what is your question?

You already asked me this before. My question is in reply #191.

[Jaaanosik (OP)]

There is no wobble from a single gyro in micro-gravity, check the video.

I can see it wobble. The wobble is just very small.

Please, what is your question?

You already asked me this before. My question is in reply #191.

Dictionary is not a textbook, and even textbooks can have mistakes,
Jano

[Kryptid]

Dictionary is not a textbook

Your point being what?

There is no answer till we settle the closed system definition.

The spaceship is an isolated system. That is clearly defined. No matter or energy is entering or leaving the system. No momentum is entering or leaving the system either.

So if a system does not have momentum entering or leaving it, you understand that the momentum must remain unchanged, yes?

[Jaaanosik (OP)]

There is no wobble from a single gyro in micro-gravity, check the video.

I can see it wobble. The wobble is just very small.

Please, what is your question?

You already asked me this before. My question is in reply #191.

Yes, there is very tiny wobble on the gyro ring, but check the axle, no wobble at all.
The wheel could have a wobble due to bearings the axle tells the story though.
It appears the axle might be slightly bent on the bottom part, the top part seems straight, without any wobble,
Jano

[Jaaanosik (OP)]

Dictionary is not a textbook

Your point being what?

There is no answer till we settle the closed system definition.

The spaceship is an isolated system. That is clearly defined. No matter or energy is entering or leaving the system. No momentum is entering or leaving the system either.

So if a system does not have momentum entering or leaving it, you understand that the momentum must remain unchanged, yes?

Check the cat.
Forget that the cat stopped the rotation.
What is more important is to realize that the cat was able to start the rotation without external momentum.
Do you understand what it means?
The cat is isolated system, correct?
How the cat could start the rotation without an external impulse?
Jano

[Kryptid]

Do you understand what it means?

Yes, it means that executing a rotation does not require net momentum (unlike your engine, which does require net momentum).

The cat is isolated system, correct?

For the sake of discussion, yes.

How the cat could start the rotation without an external impulse?

Because net momentum isn't needed for a rotation (but net momentum is needed for your spaceship to go forward). I've already said that before.

The thing about the gyroscope is ultimately irrelevant. Even if I was utterly unable to explain anything about gyroscopes, I can still point to Noether's theorem as proof that you can't interconvert angular and linear momentum.