swansont

There are two wave behaviors to consider: the wave function, from Schrödinger’s equation, and the matter-wave behavior from deBroglie’s equation. The two are not identical. The “collapsed state” issue applies to the former, not the latter. IOW, you will still have wave behavior even in a single quantum state No, I disagree. Quantum particles have quantized energy and a localized interaction region, which are not wave behaviors.

Right. the force exerted on the object is in the FBD. The force exerted by the object is not.

I see something

There are chemicals used in smoke/fog machines.

I wasn't aware the Wikipedia prevented editing or participation based on geography. If you Google free body diagrams, you will find plenty of the other kind Take a peek at one of the permutations of Halliday & Resnick, a very popular into to physics textbook https://www.wileyplus.com/physics/halliday-fundamentals-of-physics-11e-eprof18272/ No, and using the dot renders that moot. By the diagram? It was only recently posted.

I wonder if this convention is geographic in nature. FBDs I have seen and made look a lot like the one shown. That is unfortunate, but otherwise the arrows would have to overlap, which might be more confusing. Given that action-reaction is typically introduced very early in the curriculum, I am also sure it's not intended.

I don't see meartha in your equations (i.e. the reaction force to the weight of the book). And you have not labeled your normal forces to indicate the source of that force. The normal force of the book on the table, or the normal force of the table on the book. Only one of them appears in an equation. Not both. What is F in the equation? It's not given in the problem. Whether the weight and normal force are equal in magnitude has nothing to do with action-reaction. FAB = -FBA There are no caveats on that equation. If the book is in freefall, the earth still feels a pull from the book, and the two forces are equal and opposite. mearthaearth = -mbookabook There is no way I can reconcile this with Newton's third law. The weight of the book is not something that is acting on the table, as the weight of the book is not a gravitational force. The force the book exerts on the table is a normal force. It's a true statement, but it's not just that it's two different objects. It's the same two objects, and category of force. I would say that your statement is less precise. Gravity acts on the book, and on the table, so that's forces acting on two objects. But those are not an action-reaction force pair.

In a valid free-body diagram, no action-reaction force pairs will appear. Because in a FBD, all forces are acting on the same object, while for action-reaction, it's a force acting between two different objects.

Your question is a mainstream science question. Yes, I have. PhD in experimental atomic physics, so I have used vacuum equipment for a long time. I've been through multiple iterations of having to fix vacuum problems. And so I know that you hadn't given enough information to diagnose the problem. (also, being a scientist, I wouldn't be using inches of Hg) Like I said, it could be the gauge, it could be the pump, it could be a leak. You didn't tell me what kind of gauge you were using - it matters. You didn't say anything about the setup - it matters. It gets harder and harder to lower pressure the lower the pressure gets. A mechanical pump will only get you so far (a good one gets you to the low end of "low vacuum" in the list Strange presented). All systems leak; the question is how much. Outgassing and virtual leaks will limit you as well. For good vacuum one bakes the system to speed up the outgassing, but that's usually not an issue for just a mechanical pump.

Action-reaction pairs don’t compensate for anything, either. They don’t appear in equation of motion because one of the forces doesn’t act on the body. There is no composite system under discussion. That’s a distraction to the question that was posed. The question asked gives no reason to look at the book+table system. The issue of misidentifying action-reaction pairs is a quite common misconception that students have, in my experience. It’s best not to feed it.

Whether they cancel doesn’t matter, since cancellation requires that the forces act on the same object. Action/reaction pairs act on different objects. They don’t cancel. Bringing up misconceptions in discussion often has the unfortunate effect of reinforcing the misconception. When one later recalls the information, the fact that force cancellation were part of the conversation will be remembered. (when I taught we called this the “not” filter. If you tell someone that X is not true, they will remember you saying that X is true.)

Gravity is a force the earth exerts on the book. The reaction for this would be the gravitational force the book exerts on the earth. The reaction force to the normal force exerted by the table on the book would be the normal force exerted by the book on the table. In both cases, the force pairs are exerted by one object on the other. The forces are the same type. In the example, neither of those is true. The action-reaction force pairs are in opposite directions and equal in magnitude, which is also true in the example. (and can’t be used to draw a conclusion in this example) Irrelevant, though, to the issue of action/reaction force pairs.

Doesn’t matter if it’s obvious to you. Theory says the electron is a point particle and experiment backs this up. Can you transform into a frame where angular momentum goes to zero, the way you can with linear momentum?

Are you arguing philosophy or physics? Last I checked, gravity was in the realm if science. IOW, what evidence do you have that e.g.an electron doesn’t experience gravity? And if they don’t experience gravity, do they also not exert gravity?

Electrons can become bound to an atom, but they have to lose energy to do so. Bound systems have a negative net energy (where potential energy is zero at infinite distance, and otherwise negative, owing to the net attraction)

Both can happen. Electrons are subject to the electromagnetic interaction, so they can interact at a distance, and strip an electron off, as long as they possess sufficient energy to do so. Low-energy electrons can also become bound to atoms, forming negative ions.

Simplifying as introductory physics tends to do. There’s nothing wrong, AFAICT, with the book’s example. It’s not an action-reaction pair. Newton’s 3rd law applies to all forces, gravity included. This is overthinking the problem, IMO. Ghideon’s answer was correct. Everything after that has only confused the issue

Why?

No, it just means everyone knows what time it is/was in the camera’s frame

My telepathy reference was in regard to you expecting people to know/understand things that you have not divulged. Not the operation of your device. One thing that will be true is that pressure differentials will be limited by the pressure present, if you want air/wind to move anything.

Have you explained what you mean by this? Contrary to your stance on this, such detail matters, as telepathy is not real

There is no "actually" here. The strike is simultaneous in one frame, but that frame is not preferred over any other. The observers will disagree about the relative timing of the strikes, and each can say their observation is correct and in accordance with the laws of physics. The video timer disagrees with the viewer's clock. One can choose a reference frame for convenience and/or convention, but that does not make it an absolute frame.

Air is matter, but it's not particulate matter. It's a gas. Vacuum pumps don't work equally on all gases, but that's not likely the issue here. It could be the pump, it could be a leak, it could be the gauge. I've run into all three problems in vacuum systems where the indicated pressure did not fall very much.

OK, there’s a pump. That’s a detail not originally included. You’re moving matter around. Gas is matter, so knowing details is important. If it’s full of smoke that might be a problem, since particulates might be clogging the pump and/or gauge.

Flat would be a matter of degree. Curvature small enough it can be ignored. Warp drive is science fiction.