swansont

There are biologists out there who believe in creationism. Probably geologists, too, who think there was a worldwide flood. I think perhaps you can answer the exam questions by knowing the answer "they" want without actually believing it, or perhaps not understanding the ramifications, and still get a passing grade — and with it, a diploma.

A given mass at a higher speed, and thus more energy and momentum (and can be applied to any unit of mass ejected), will go a greater distance in an open space. But that's not the same as "more propulsion" which depends on the momentum of all of the ejected fluid. You have to de-couple the two in asking your question. What is it you want to optimize? That's biology, not physics.

White "It is a naturally white and very brittle (prior to the additions of plasticizers) plastic" https://www.creativemechanisms.com/blog/everything-you-need-to-know-about-pvc-plastic

That's a tough question to answer. It isn't always obvious how a misconception gets affixed in someone's mind. But this is such fundamental physics, and we have the obvious word salad, which is what leads me (and others) to conclude that this is not a physicist.

Why not? How does a charge carrier get ejected fro the wire without experiencing a force, and why will that not exert a reaction force on the wire? And so so on, because all the charge carriers electromagnetically interact with each other. It seems like you are just assuming they don't, and then coming up with a solution that violates conservation of momentum. Those who have experience solving such problems know that an apparent violation of a physical law often points back to a faulty assumption. You just agreed that attachment isn't necessary. An ion current will have mass and momentum and you need to account for it in your analysis.

You don't show a current flowing from D to C and say "IF, the circuit were to be closed with a wire from D to C, the total force on DC would cancel out the total force on AB." which means there isn't a closed circuit. Your OP talks of a hypotenuse, so you did not make clear any connection between it and the diagram with thr rectangles (which are not right triangles.) You need to disabuse yourself of the notion that your posts — which you've admitted to conceiving while you are high — contain coherent explanations. You have not supported this assertion with any physics. Why would there be no force on the structure? The electromagnetic forces do not require any mechanical attachment.

I don't think I was "teaching" You seem to be in lecture mode, not student mode (if it was the latter you would be asking questions, rather than insisting that certain things are true) You ignored part of the circuit. Of course you will get the wrong answer. Without a circuit, there is no current. Why would you assume there is no force on an arc?

It may be a geode. Geodes are rocks that are hollow, and can have some sort of crystal formation inside them. If something has broken off inside, that could be the rattle you hear. https://en.wikipedia.org/wiki/Geode "Geodes can form in any cavity, but the term is usually reserved for more or less rounded formations in igneous and sedimentary rocks. They can form in gas bubbles in igneous rocks, such as vesicles in basaltic lava; or, as in the American Midwest, in rounded cavities in sedimentary formations. After rock around the cavity hardens, dissolved silicates and/or carbonates are deposited on the inside surface. Over time, this slow feed of mineral constituents from groundwater or hydrothermal solutions allows crystals to form inside the hollow chamber. Bedrock containing geodes eventually weathers and decomposes, leaving them present at the surface if they are composed of resistant material such as quartz.[1] When cut in half, visible bands corresponding to varied stages of precipitation may at times show patterns that reveal points of fluid entry into the cavity and/or varied colors corresponding to changes in chemistry."

If you are insisting there is a net force somewhere, then yes, we want to see a calculation. Your OP seems to claim there will be a net force, but later you admit that the force on different parts of the circuit will cancel. Which is why I said you need to explain things better. Your claim is unclear, which causes difficulty in figuring out what you are trying to explain. Berating people for asking you to clarify makes things worse.

I agree it's nonsense. While there are some physicists who just don't seem to be able to engage on simpler levels, there's no real reason why one can't have a discussion of this subject using basic Newtonian physics, and first-order approximations, in which case, a non-rotating planet is a sphere and there's no need to invoke any of the word salad to try and masquerade the nonsense. There might very well be a few physicists out there who believe in a flat earth, just like there have been some who reject relativity or quantum physics. Not everybody is good at what they do.

! Moderator Note Using dropbox to convey information about your conjecture is a violation of the rules. Do you understand this? Come up with a model to explain why we observe time dilation in clocks that don't have an explicit dependence on g (e.g. atomic clocks). Alternately, show the explicit dependence on g for an atomic such a clock. (I mean, let's be honest — using a pendulum as a counterexample for gravitational time dilation clock shows a spectacular failure of understanding of the issue)

! Moderator Note The burden is on you to provide information about your conjecture. people don't have to justify pointing out things that are incomplete, incoherent, or contrary to mainstream physics. If the circuit isn't completed, there is no current. So you have no force. (also the current FE must be 2I, if you had a closed circuit) I have no idea what your actual claim is. You need to explain it better.

The overall effect is only about 0.1% of the solar radiation, so you aren’t going to see a huge shift

This is one of the reasons that physics doesn't tend to rely on the terms future/present/past. Language is sloppy and imprecise, and relativity makes a further muddle of relative timing.

F = ma If F ≠ 0, there must be an acceleration You can't have an unbalanced force and no acceleration

The zero point energy is the energy when the system is unoccupied, or in its lowest state, depending on the system you're describing. It's an energy, not a state.

You have to be careful with definitions here. W = mg and that is *essentially* unchanged, as Markus notes, as long as you're near the surface. g is basically the same value. But the net force changes, as MigL notes, owing to the buoyancy from the water, which is equal to the weight of the water displaced, which in this case is 4.81 N. From that you could calculate the volume of the spear, and thus its density (and maybe that could tell you what its made of. It's a little too light to be aluminum*) *edit: solid aluminum

A participant. Annoyed at misinformation being perpetuated, which mucks up the conversation What I'm asking is that if you want to critique, can you use an example that is not blatantly wrong, and also grossly atypical? And also saying it's helpful to have scanned the thread to see if your point was addressed already.

Can we stick to the topic? Raider's example is not only wildly atypical (they even linked to an article about how only a small fraction of debt even hits $50k and blithely suggests that coming up with $70k of extra cash right out of college would be easy) it misrepresents the plan — it ignores the $50k cap, and if the debt is unpaid for 10 years, that the debt will be more like $115k (5% compounded). It's not getting wiped out. And it was already addressed that no, if you paid off your debt, you don't get anything. By the same token, if you didn't have (adequate) health insurance 12 years ago, you aren't getting your medical bills paid off either, even though the ACA later kicked in. The idea is to level the playing field going forward, not invent time travel.

Part of that is that you shouldn't be asking me independent questions. That's thread hijacking. That's why I was tying my answer to the discussion with scuddyx. My "evasiveness" is an attempt to be within the spirit of the rules. I think you could set that up in a way that was like passing near a massive object. (It would have to be very massive, though, and/or the index very close to 1) What you describe is called a GRIN (gradient index) lens, where the light continually refracts, rather than just doing it at the surface as in a traditional lens. Gravitational lensing is a real effect, so I'd say it's not meaningless. But it depends on what you're trying to demonstrate. Further discussion should be in a new thread.

! Moderator Note That's because you did not present any in the threads you started, and YOU WERE TOLD NOT TO RE-INTRODUCE THE TOPIC WITHOUT THE EVIDENCE. Is it really surprising that the threads were locked, when you don't follow the rules? Will it really be surprising to you to be suspended and/or banned for repeatedly not following the rules?

My previous answer was to the claim that it is always advantageous to travel near a massive object, which is patently false. As I had said, a photon going to a distant planet in the opposite direction doesn't gain an advantage by detouring around the sun. The only way for that scenario to happen with simultaneously-emitted photons is if one goes through some medium to slow it down, or you bounce it off a mirror, but the photons will be taking different paths. So then you aren't comparing apples to apples. You could do it with and without the massive object at two different times, but they still won't travel the same path. If the photons don't travel the same path, why is there an expectation that the travel time would be the same?

It would be nice if you could find a link to that. Sometimes the diagrams are schematic in nature, and not meant to be taken literally. e.g. it might represent reflection, or absorption that is reradiated outward. Can't tell without looking at it like this one (the lines do not represent the actual path of the light) https://marine.rutgers.edu/cool/education/class/yuri/erb.html

These are not terms generally used in physics analyses.

That's a separate question from the one I was answering, but the path around the massive object will also be length contracted. Locally, an observer anywhere on that path will measure the light to be going at c. I am not addressing the problem of having two paths that fit your criteria, which seems unphysical.