swansont

In your diagram you say the velocity is not zero, so there is motion along the axis of rotation. Why are you all of the sudden claiming there is none?

One example of education breeding better education. If the parents don't know this information, they can't pass it along. Puts the kid behind others who know their way. If parents are illiterate, they aren't going to read to their children, which is something that boosts kids' education. If the parents are working multiple jobs, they might not have the time to read to their kids, or take them to the library. So poverty is an impediment. (and of course poverty has connections with racial inequality) In the US, the education system is funded by property taxes, so in poorer areas there is less funding. Not as many resources. Another way poverty is an impediment. (there are more, too. Health is anther factor. Nutrition.) Bootstrapping is possible, but it's still an impediment, regardless of how many examples one gives of people doing it. It's wrong to say barriers did not hinder people, if all you know is the result. All you can say is they did not stop them.

! Moderator Note Let's keep to the topic of calculus here. If you want to ask about this (or anything else), please open another thread (in physics, in this case)

They are not opposing normal forces, and they are not collinear because the surfaces are at different orientations. They are normal forces from different contact points of the nut and bolt. One is from the flat part of thread-on-thread contact (N1) and the other is on the edge of the thread, contacting the housing of the nut (N2). They are both forces exerted by the bolt on the nut, and each has a reaction force exerted by the nut (these are not shown, because I am describing the forces exerted on the nut) The radial component of N1 is balanced by N2. We know this has to be the case because the nut does not accelerate in the vertical direction. The axial component of N1 remains, and is the reason the nut accelerates.

If MSC chooses to return (with perhaps a slightly thicker skin), then perhaps they will be willing to do a little legwork to prove that we should have a these suggested subsections inside of philosophy by providing us with some statistics of how many e.g. logic threads exist already. Maybe going back a year. Along with some examples so we can check the data. In addition, they could also tag their thread titles (e.g. Some title [logic]) so we can track what happens. With that and other suggested subsections (Meta-ethics, Metaphysics, Epistemology, logic, aesthetics and Phenomenology) You seem to be missing the point. I didn't say we don't apply logic, or that we don't understand logic. I didn't say you don't need to understand logic to do science. I'm saying we don't have to have discussions about logic in order to do good science, which is the kind of discussion you would expect in a logic subsection. You can say the same for math. Physics uses a lot of math But you can have physics discussions independent of the math section, because you don't need to contemplate the purely math considerations. You are using the math, but you are not discussing the math. You can say you need to integrate the force dotted with displacement to get the work — that's a physics question — but that's not a discussion about what a dot product is, or what an integral is, which is what you might discuss in mathematics. IOW, we don't have a mathematics section because you need it to discuss physics. We have a mathematics section because there is a lot of traffic in people discussing mathematics. Which is why "Without logic, no science" is a non-sequitur for making the case of having a logic subforum.

"Military qualities"? Any evidence that evolution happens this quickly? And evidence that sexual dimorphism is disappearing? I'm pretty sure the average height of men is still greater than for women. And weight, strength, etc. We've been doing agriculture for many thousands of years. If it only takes 1000, then there should be none of these differences.

If there was a net radial force that pushes, the nut would accelerate in that direction. Why doesn't it? Because it pushes up against the bolt, and the bolt pushes back with another normal force. (edit: bolt is blue, nut is orange) The radial component of N1 cancels with N2, leaving no radial force. There is a net force along the axis. (I am ignoring friction, which will balance this out if there is no acceleration) N1 and N2 each have a reaction force from the nut acting on the bolt. If there are reaction forces (and there always are) then there is nothing "reactionless" about this system. Mechanical advantage has nothing to do with this. If there is a net force, there will be acceleration (Newton's 1st and/or 2nd law. Take your pick) Gravity in this case is basically doing the job of your motor in your machine, except it's the nut that's rotating.

The net force is along the axis. I will work on a drawing to show why (I’ve realized my earlier explanation isn’t quite right) The fact that there is a component along the axis is sufficient to prove it’s not reactionless. The normal forces of the nut and bolt are an action-reaction force pair.

Since F_A is not a force the bolt exerts on the nut, I am certainly not talking about it. And you should stop, too. It’s wrong to include it.

You can spin a nut freely on a bolt. there is no net radial force

If they exist they would be in the philosophy section. Same would be true for French, English literature, history, music, and many other subjects. We don’t have those sections either.

The wave function collapses for each particle when it is detected

I addressed this already. You have shown only a single point of contact. When you integrate over 360 degrees (one full traverse of the circle), the radial components cancel. Also it’s not reactionless. There is no reactionless force. The nut exerts a reaction force on the screw. There is no reactionless force. The magnetic materials will be exerting the action and reaction forces. They would be magnetic forces in this case.

My work colleagues and I manage to do quite a lot of quality science without having discussions that would be put into a “logic” section. What happens when you get a contradiction of the premise in a logical argument?

So it’s not that you want to study EM. What is this “transition”? The detection is both - you detect particles, and it follows the interference pattern. The more you detect, the better your statistics get (to first order, anyway)

Nobody is claiming that the site is free of the use of logic. Logic is not a required topic of discussion when discussing science. Feel free to peruse the science threads and see how many of them do not go into discussions of the finer points of logic. IOW, no logic ≠ no logic section But hey, nice strawman.

To follow up on this, the philosophy section has just under 29,000 posts. Physics, chemistry, biology, medical science and mathematics all have more. By a lot, in most cases. That’s one of the reasons they are broken down. Also because we’re a science discussion forum. We include philosophy (and other topics) because there is a natural spill-over in discussions. But the primary focus is science.

That’s a description of how the device works. It is not, however, a physics analysis. F_A is not a force the screw exerts on the nut. It is exerted on the screw, so it has no part in the analysis of the motion of the nut. There is friction, and there is the normal force, which, when accounting for the entire thread, is along the axis of the screw. It’s not reactionless, and is why the mass moves.

Bound systems require a decrease in energy. (If the KE exceeds the magnitude of the PE, the object in question can escape and is therefore not bound.) Normal matter clumps together because their interactions can easily dissipate energy and form bound systems. Gravitational interactions are really bad at dissipating energy. (Gravitational radiation is weak) That’s why DM tends not to clump, or would not (by itself) tend to form a black hole

iNow already asked for you definition of utopia. You also need to define “best” in this context. Is “best” meaning that the maximum number of people live in comfort, or that a minimum don’t suffer much, or what? (these measures would need to be quantified or defined) ”the best world” is way, way too vague

Any mass element curves spacetime outside of that element. The effects of multiple mass elements combine (i.e reinforce each other)

! Moderator Note We need some physics in discussions about physics.

! Moderator Note The experiments exist. There are youtube demonstrations of this. You already had a lengthy thread where you made your unsubstantiated claims and ignored feedback, and you were told not to re-introduce the topic.

“Input force”? That not something that goes in a free-body diagram. It doesn’t matter why the screw turns. You already agreed that the normal force is the action force. The latter should not appear as an item in the drawing; you already accounted for it. Newton’s second law tells us that the acceleration of an object is the result of the forces acting on that object. Your “input force” is not a force acting on the nut. The screw pushes on the nut - the normal force. There is friction. There is no other force present.