Title.

I need some back of the napkin math. I’ve got a ~300lb person who I want to put at an angle while laying in bed. I want her to use the foot board of the bed for some partial weight bearing. The foot board has a limit of 180lb. What’s the max angle we can tilt her bed to stay within that 180lb limit? If there’s a better spot to do this I apologize, it’s just been a minute since I’ve done this math. Thanks, not homework, I work in a hospital. Is it as simple as 45 degrees would be ~150lb of force on the footboard? Half and half…

We are fairly certain that almost all the laws of physics treat positive matter and antimatter identically (except for the weak interaction which interacts with the opposite chirality of each particle). Given this, do we know that distant celestial objects aren't made of antimatter to the same degree that our universe is made of positive matter? This feels like a relatively straightforward resolution to the antimatter asymmetry problem, but I am also pretty certain I can't be the first one to think of this, and the problem remains unsolved, so what's up?

Many people suffer from chronic, congenital depression. But are there people who are naturally happy 24/7? As far as I understand, people with depression feel very bad 24/7. So, are there people who are extremely happy every day? I hope you understand what I mean. Feeling extremely happy as if you were using cocaine, heroin, or alcohol for the first time every day

In GA the E and B field can be define as bivectors. Does anybody have a geometric visualization that could motivate this? The interpretation of B as a bivector I think can be seen well when looking at Lorentz force and circular motion of an electron. But is there a further intuition for E and the resulting F?

I just started studying physics this year, the first semester is gonna be over soon and while I'm doing well and l've enjoyed this first months, I feel like so much homework sometimes pushes me to do the exercises as fast as possible just for the sake of finishing rather than actually understanding what you are doing, so can anybody tell me what should I have a good understanding of after this first six months? more than anything to study in winter break thank you!

I get that the angular momentum stays the exact same but still the speed changes, shouldn't that cause some effect due to inertia

So in my ap physics class i got into an argument with a friend who was insisting the Big Bang needed a cause. I insisted that it didn't because time wasn't the same during the period before the Big Bang so it did not need the initial cause. What are your guys opinions on the Big Bang? Does it need a cause?

Spontaneous generation states that living things can emerge from non living things. But then scientists like Redi disproved theory centuries ago. But the bing bang can be taken as living things emerging from living things? As I heard there was a dense point in the beginning of the universe, emense energy condensed into one point called the singularity. Unless things have changed, energy as we all know is non living thing. We wmeeged from that thing, star material which also non living thing.

Edit: I seem to have mistaken spontaneous generation with abiogenesis. But still lets talk about it

Suppose a 3 mass system of masses A(2m) B(m) C(m) are on a horizontal frictionless surface such that B lies on the middle. 2 springs of spring constant k are connected between AB and BC. Moreover A and C are clamped by a rigid rod which lies over them. If B is given velocity v horizontally, find the maximum compression in any spring.

Pls provide an intuitive explanation rather than using some "known" results, would be really helpful.

I have not gone to college, but that hasn't stopped my life long passion for science!

This year, I've been journaling, for creative, historical, and scientific purposes. Throughout my time so far, I've filled out three and I'm still going to write more.

I have so many hypothetical thoughts, questions, and ideas.

I really want to talk to my fellow humans and pull our information together. I've got the questions and ideas, so please give me your academic knowledge, so as we might finally continue our evolution as a species. I have not given up on humankind's dream of space travel. I have ideas for artificial life. I have theories about our evolution.

Just please, I need you guys. I need your passions to help keep me motivated. I need your input to help solidify my own ideas.

I am not just looking for scientists of physics, but Scientists. People who are so fascinated with our world, that you dedicate your lives to learning about it. Please help me. I want to know more.

Tell me what interests you. Dm or comment, I don't mind. What have you been studying? What are you truly fixated on?

I've got questions for science, history, and math. Various sorts for various occasions. Let me know what you know, so I may ask questions to learn more.

Thank you for your time!

Hello. I'm not a scientist but i just have a question. We know speed of light is finite. And we know photons don't have mass. An object with mass needs infinite energy to reach speed of light. That seems paradoxical to me so i have a few questions to real scientists here:

1- Do we say an object with mass needs infinite energy to reach 299,792,453 m/s because its the limit or is it actually calculable?

2- Is there any way that photons have mass and the speed limit of the universe is something higher like infinite speed?

I'm sure this is a flawed, but if we know we can't go 100% the speed of light, intuitively it would seem that we could identify how close we are to that limit.

Does there need to be some non-existant reference frame to answer this, while the restriction of 1c is true in every conceivable reference frame?

Bell’s inequality assumes uniform distribution of photon polarization. The experiment makes assumptions, but doesn’t verify them.

1. It is possible to create a setup that has perfectly uniform polarization distribution through all time.

2. There are an infinite number of polarizations possible for a given initial quantum state.

3. That the number of occurrences of the test is sufficiently high to approximate N=infinity.

To my knowledge none of these have been addressed. The measure of randomness of polarization doesn’t prove infinite polarizations, only suggests the pattern of possible polarizations is balanced. This can be true even for small values of N, but doesn’t mean that the infinite range of polarizations is producible.

Since the Bell test is fundamental to the behavior of entanglement, I would expect these things to be addressed. However, it seems that the test is necessarily constructed in a way that makes it impossible to verify the assumptions, making the experiment unfalsifiable, and therefore irrelevant.

Can someone please explain what I am missing?

Hey guys, I am working on my Bachelor’s thesis and my subject will be physics in the anime One Piece. I am interested in some conversations about the topic and/or ideas regarding the topic as well, just want to have fun and talk physics. Thanks, everyone.

Just like we use light as a constant to measure distances because it never changes in vacuum. Is there some object or thing in the universe that hypothetically could be stationary and what would it likely be?

This question might be a little broad, but from what my Introductory physics textbook says, Lattice QFT is an alternative method of describing/approximating interactions between particles by representing them as 4D crystal-like structures with nodes and connections. The book doesn't really go in depth, it just casually mentions them as an alternative way to visualize interactions compared to Feynman diagrams.

I was wondering if anyone could explain a little bit more about what these metaphorical crystals and their components represent?

Physics undergrad here. I know that a lot of undergrads have started using chatGPT as tool, and also as quick way for solving homework. While it isn't right 100% of the time, it does give out good answers on basic problems, and is good at explaining stuff with plots and code.

These features made me inclined to belive that it may be quite useful to learn physics using it. Its also good at pointing to sources like free notes and online lectures. Opinions?

Note: This is my experience with ChatGPT 4o, i.e. I have a subscription.

I'm a bit lost in QFT. We often talk about ⟨Ψ|Ô|Ψ⟩, a particularly nice case for |Ψ⟩ is |n⟩. For EM we usually speak in terms of F^(μν) or A^(μ), whichever is fine.

Q1: Can someone please write an example of |1⟩ as an explicit function (x,y,z) in the context of EMs field?

Q1.3: In QM |1⟩, corresponds to a time dependent solution Ψ_1 = e^(-i E_n t /hbar) |1⟩ =|1(t)⟩ . What would the time evolution of the |1⟩ above in Q1 be?

Q1.5: I'm interested in Ψ as a function of time. Is that problematic? So I want |Ψ⟩ in Schrodinger picture, not Heisenberg's.

Q2: What about |2⟩ as a function (x,..,x',..)? I think |2⟩=|1⟩⊗|1⟩ is sufficient.

Considering buying a poster as a gift / decor, and I'd like to know if the info on it is actually correct (other posters from the maker have been known to have typos, inaccuracies, etc). Not my field so I can't properly verify, but the person receiving would definitely notice if there are any! Thanks in advance, kind smart people :)

https://m.media-amazon.com/images/I/81ZwHPcyh4L._AC_SL1500_.jpg

I am reading 'A brief history of time' and in that there's this example talking about how objects moving at speeds significantly less than the speed of light will not follow E = mc².

I am confused with the maths in this example. Please know that it's been really long since I touched maths or physics. So can anyone help me understand?

In the example it says - at 10% of the speed of light and object's mass is only 0.5% more than normal, while at 90% the speed of light it would be more than twice its normal mass.

1. So how is the statement making sense?? Can anyone please explain.

2. Should I not use E=½mv² when the object is supposed to be moving at speeds 0.1c or 0.9c?? But then the speed is not equal to that of light, hence i thought I should use this only.

3. What is the meaning of "0.5% more than normal mass" or "more than twice its normal mass"? What does the author mean by "normal mass".

Are Casimir Plates available for purchase online? I've looked at numerous scientific equipment sites but haven't been able to find anything.

I'm sure questions like "is this worth it" pop up here often, but I've genuinely spent way too much time contemplating and would like some input from someone more experienced (maybe even from someone in the field?)

I am fascinated by physics and astronomy, but it almost feels like I'm not cut out for it. I've always been interested in space, and I by some insane miracle got into a top uni in my country with an amazing program, very intense but it could get me into an actual space science institute to do research in my third year already. But, I was severely underprepared. Due to bad mental health I didn't study anything deeper than what was needed for high school graduation exams (I guess it's somewhat similar to SATs?), and when I got in, I only spiraled more because I couldn't understand anything, and the dread of trying to understand it only made me procrastinate and understand even less (and feel extremely stupid).

I dropped out. Since then, I've just been so painfully confused. I don't know if I like studying physics, or the idea of it. I've almost made a decision to just screw it and go into some other major (computer linguistics? Because, I don't know, I'm okay at languages and it would still provide some math/coding knowledge?), but nothing seems to really appeal to me as much. I'm 20 and not in uni at this point, but I'm trying to pick up physics again — just started reading "Physics for scientists and engineers with modern physics" by Serway/Jewett (for some reason I cannot stand reading textbooks in my native language), I'm hoping to figure it out...

Another thing that worries me is that I'm concerned about the money. I'd like to do research, I think? But all I hear is that it doesn't pay well, and I'm not sure I want to teach in addition to that. Does caring about this stuff mean I don't care about the science? And, for some reason it doesn't feel very compatible with a life I want (namely good/comfortable pay and a good work-life balance), but at the same time I don't have anyone to ask about it anyway so I could be wrong.

I'm sorry if I'm rambling or if my questions are dumb, I'm just a bit desperate and frustrated that I've basically made no progress in anything at all over like 2-3 years :/

Thanks in advance if you even read this. Hope you have a good day!

I am finally ending my undergraduate studies. I love physics as a subject and I tend to be very active in different areas that I find interesting (currently working on numerical relativity). I want to study abroad and possibly in Europe or North America. I know there's a good deal of people also trying to get into these universities.

The problem is that I don't have a bright transcript. I didn't (and still don't) value numbers on a paper, to be honest my university is famous for hard exams (University of Tehran), and I never cheated or even tried to... despite that I can say comfortably that my CV is interesting (I worked in multiple research projects, in numerical relativity, simulations and computational physics, as well as some philosophy of science).

1. What are my chances? I'm really worried since most universities have high GPA's as a way of evaluating my worth.
2. What would be a good strategy so that I can prove that I'm capable despite my grades?

Bests to all of you :)

PS any university would be good since I really don't like staying in this country.

I have a question. Why do metals and insulators have different energy band gaps

I can see how two ripples interact on the smooth waters surface if I drop two pebbles and watch the waves interact, but how is that if it was two spheres interacting? I am struggling to envision that. Serious question.

I am not a physics student or anything, but am just interested in this. I understand a little bit about the four vectors of velocity and how the sum is always c (and how that correlates to time “slowing”/“speeding” up for objects at different spacial velocities).

But I just don’t get it why an objects “falls” due to gravity, I understand that it moves along the curved lines of space-time, but if the object didn’t have a starting velocity, what made it “move”?

I know that analogies don’t really help because at the end of the day, I’d need to know the math behind it, to really understand.

Hi people , I was trying to find any drawing online of a microscope ray diagram consisting of 4 lenses as in 2 in the eye piece and 2 in the objective , or something similar as the 2 lens physics demo models seemed a bit too simplistic , please link any resources that could aid me.

Say we had a circuit like this: battery's anode-wire-bulb-cathode

If we doubled the length of the wire, there would be twice the resistance - why - because the electromagnetic field has to do twice the work (accelerating twice as much electrons which collide with nuclei) at any given time, right?

Also: would the bulb glow less bright with more resistance - is it voltage or current that makes it burn bright - current would stay the same, right?