Thoughts Definition and 362 Threads

Same instruction was given while finding value of 'g' by a bar pendulum. In the former case,does the spring obeys hooke's law while it forms a coupled harmonic oscillator system?Does the bar pendulum somehow breaks the simple harmonic motion(such that we can't apply the law for sumple harmonic...

Looking for something else I just stumbled over this paper the declare as introducing a field they call "bayesian mechanics". I thought I would create a new thread for a change and just highlight this paper. It's the first time I've seen this from the authors so I don't have their full...

Hello everyone. This is my first post here. I hope that you had a good Christmas eve and that you are in good health. Recently I graduated with a B.S. in Mechatronics Engineering, and I got a job in a local manufacturing company in my hometown. Before proceeding with the post, I want to say that...

Thinking about Bell's string paradox , I understand that if both spaceships maintain the same and constant proper acceleration, the string breaks because of the non-simultaneity of the acceleration effects at both ends of the string. But I want to introduce and consider a slight and subtle...

Having read a fair bit of SF down the years, and now pondering the likely future direction(s) of the smartphone, I do wonder about the practicalities of the oft-cited videophone. Yes, the advantages are clear in domestic settings; that's to say using fixed screens on to which relay video images...

Well since we count all possible posts , including those that have no syntax, no proper grammar or proper words, and no sensible meaning, all posts of length n are something like 100^n (I suppose we have 100 possible chars besides the letters of ordinary alphabet, including symbols like the...

Suppose you have a heavy body placed on a surface. We apply a horizontal force such that it is on the verge of moving (maximum static friction). We measure this force and note it down. Now we cut the body from the top and remove a thin layer and again do the same thing. We apply a force and...

Imagine a solid body big and heavy. It will have friction between it and the surface when tried to move. Somehow the cluster of molecules opposes the push. When free these molecules stick on surface and can be moved by a mere blow of wind but when bonded into a solid body the structure of large...

Water is made up of loose molecules but a body like ice is bonded strongly into a shape. Imagine a ice brick. It will have friction between it and the surface when tried to move. Now it slowly starts melting. The molecules of ice will start sticking on the surface. Somehow the cluster of...

The weird thoughts you have at random times

Hi there, I am currently reading introduction to Chemistry fourth edition by Bauer, Birk, Marks. what do you guys think about this book? is it a good book? I am doubting the quality of the book because I found one wrong statement about the reaction of Alkaline Earth Metals. It said "Alkaline...

I'm a second-year student and I'm trying to increase my knowledge of physics and engineering by designing a gun capable of loading and shooting very hot loads and at the same time converting the recoil energy into something more useful and or more manageable. as we all know the recoil and...

A year ago, I asked a question about two journals, both of which were predatory ( https://www.physicsforums.com/threads/are-open-access-journals-legit-for-my-cv.990744/ ). Thanks to the overwhelming advice I have received, I did NOT publish in either of those journals. Right now I am asking a...

For a metrology (power metering) calibration test fixture at work, I'm looking for a low-cost way to generate an isolated 120Vrms (or 240Vrms) sine wave to feed into the high-impedance mesasurement circuitry. The first test fixture used a $40k AC Mains generator instrument driving a 1kW load...

In the industry, coal and other fuels are typically represented by - their C, H, O, N, S elemental composition for the combustible part - the composition of the ashes (SiO2, Al2O3, Fe2O3, ...) - the Low Heat Value (LHV) which is the heat that can be extracted from combustion product With...

(a) ##f(x)## is continuous only at ##x=3##: 1- If ##x\in\mathbb Q##, ##f(x)=9## at ##x=3##; around, there is ##\mathbb Q## 2- If ##x\in \mathbb R\setminus \mathbb Q##, this is the set of irrational numbers. Intuitively, if ##x## was in ##\mathbb R##, ##x^2## and ##6(x-3)+9## would meet at...

Some scholars think the world wil cap out at 10 billion humans. Humans are an Invasive species and have little to no predators in the right conditions .Using Biologly terms we would be tertiary consumers So what are your thoughts on overpopulation and how the invaive species known as...

Anyone have any thoughts on this book? I was only able to find one short review (OSA) and the book is priced proudly. https://www.amazon.com/dp/0521869021/?tag=pfamazon01-20

This is pretty amazing. Could this point to a future where we all can do this and much more with implanted brain chips?

Anyone going to see it?

(sorry i post this here now because i didn't know about this sub forum earlier) I came across an interesting paper from which I'll quote parts of the intro: and the conclusion: obviously the authors are more competent in Physics than I am - so are most PF member. what are your opinions on...

I came across an interesting paper from which I'll quote parts of the intro: and the conclusion: obviously the authors are more competent in Physics than I am - so are most PF member. what are your opinions on this? can the work of these authors "discover" physical laws in any way or is the...

So I am writing a campaign for dungeons and dragons, and I have just started putting together a part of the setting in which a kingdom was shrunk about 2000 years prior, and stored in a small container. The upshot of this (by my own authority as the author) is that time travels about 10 times as...

I watched a video lately describing how life could have arisen on Earth near the hydrothermal vents, with the exact way it formed being unknown. This made me wonder could there be a very simple configuration of DNA (or RNA?) that could give rise to life? I'm thinking the earliest life forms may...

Hey guys, I have a job offer as an aircraft fitter(assembler? technican?). My job duties will be: drilling, reaming, riveting, installing hi-locks, reading and interpreting drawings, assembling aircraft parts and other. Can you tell me is there a future in this job?. I'm afraid that robots will...

The topic of "undergraduate research" is much discussed today. Speaking particularly to engineering education, I wonder if we all have the same understanding of the term "research." I would like to hear from other folks just what they think is meant by the term "undergraduate engineering...

I recently encountered the Scratch programming language. I wonder what people think of it considering some notable (IMHO) shortfalls. I do not like the way it handles comments, the lack of returned values from "functions", and some other aspects that I think should be basic. But it does seem to...

Does anyone watch the Chernobyl tv series? https://www.imdb.com/title/tt7366338/ It has such realism you would think it's right in the scene. Imdb rated it 9.6 out 10. Did all those details in the series actualy happened? Which part is dramatization? It made me think deep into the night...

Hi. I'm in the first year of Medicine and I'm studying Genetics and Evolution. I have this doubt in the back of my mind and I'm not being able to move forward without someone explaining me what's wrong with my thinking. So I've learned an allele is a variant form of a gene, all alleles of the...

This study from Johns Hopkins University shows that even if we manage to nuke an asteroid and "destroy" it, it will have a core back, in almost 2 hours. Nuking them was a bad idea before, but now seems worse. More details here...

Why is it paired with materials science? I have not been able to find too much about it online apart from their own stuff. How different is it from their pure physics PhD program? It seems that they have a lot of required courses, although you do not need to take them if you have a sufficiently...

Hey all! I'm Alexander, after all of the exposure quantum physics is getting in these Marvel movies I decided to study up and I must say Quantum Physics just doesn't set well with me. I'm very interested in what has been made capable due to the math involved with quantum physics. I have a large...

I came across a theory called "timescape" cosmology. If I understand the theory correctly it assumes that the universe is not homogenenous due to the large voids and gravitationally bounded system. Also time would be different for the observers on these two different locations. 1- Is CMBR and...

What is the solid proof that all of our thoughts depend on the neuronal transmissions and limited by it. This is always the arguments used to prove that even if there is any hidden quantum computations in the brain, it won't affect our thoughts since our thoughts depend on the speed of nerve...

Background: I'm about to graduate with a mathematics degree(in the US), hence I have exposure to multivariable calculus, real analysis, abstract algebra, complex variables etc (no differential geometry however). I have also taken a class on QM(using Griffiths) and I saw some SR during a Modern...

After reading about Jupiter's magnetic field on ScienceAlert, I remembered another article about tree bark and magnetic anomalies (links below). I also remembered an article on birds being able to see magnetic fields as well. It got me thinking of how and if life is possible on anything other...

Hello all, I may get a contract to teach numerical analysis. I did quite a lot of numerical work during my PhD but that was a while ago. Now when I look at most books on the topic, I get the feeling that a lot is outdated, and I also feel that a lot of what I knew is outdated as well...

Hi, I am a junior astrophysics undergraduate student and enjoy physics, but after researching astrophysics PhD's, I am having second thoughts about graduate school. My impression of physics graduate school right now is that you are paid what amounts to minimum wage to work 60 hours a week for...

My mom lives across the country from me and fosters dogs that need a home. Her recent foster is a St Bernard that was given up by a family because the dog was getting too big (not sure what they expected from a St Bernard). The dog is in good hands now but I was considering paying to fly the dog...

Chart: Source. So, inflation has been low, which has been troubling economists and the FED over the effectiveness of undertaken Quantitive Easing (QE). What's the cause of this, and are banks holding onto excess reserves the real issue here? What are your thoughts about all this liquidity in...

Do you think with words? Do you feel the words follow the thought, or they make the thought? Do you hear them or see them mentally? Or do you think with pictures? Or with none of them, only pure thought?

Hello everyone, I am a die-hard tech enthusiast (probably only consumer tech), I am always interested in ever year's Consumer Electronics Show. I just wanted to create a thread discussing CES 2018 which is currently taking place. Some of the interesting things I've seen so far would...

I would kindly appreciate any corrections to my conclusions, because I need to get this subject straight for learning QFT in a satisfactory way. From what I have been reading about Lie groups so far, I have concluded the following: 1 - A group is independent of a representation, but we usually...

Post your drunk thoughts here (AKA, not thread worthy). Beer induced brain fart 1. When you microwave your dinner with clingfilm sealed over the top, the electrons in that air pocket get excited and the pocket expands (due to the air molecules moving faster right?). You get a clingfilm...

As a newly graduated mechanical engineer, I am searching for employment opportunities in my hometown region of the Pacific Northwest. However, as this area becomes more of a trendy hotspot, more & more people are moving here as an alternative to the high-priced lifestyle in California...

Hello! Manoukian's two books on Quantum Field Theory seem pretty good to me, but before buying them I would like to know your thoughts about them! Bear in mind that I need a pedagogical textbook(with good exercises if possible). Thanks!

Why nature has a lot of application of fibonacci sequence I mean why the number of spirals in the head of sunflower always has to be a memeber of fibonacci sequence, why pinecones displays similar patterns and many more examples. Do we really know the answer? I mean is this question is...

I have taken a couple of graduate level courses in quantum mechanics and I have decided to read Sakurai's Modern Quantum Mechanics from cover to cover, partly because I liked his style and I have heard a lot of people talk highly of it. But I recently realized that the second edition of the same...

Hello all, So I am experiencing a major amount of doubt about going to my phd program. I am a recent MS physics graduate with a BS in physics as well. I recently accepted admissions to a very good medical physics program in the midwest and was granted a university fellowship for a year (or...

So... I've been thinking in time manipulation "super powers" for at least three years. First i just thought "well, you have to drain time from things, don't you?" then i learned basic physics and i thought "well... that was kind of unrealistic, one actually should accelerate to a % of the speed...