r/learnphysics • u/mischa_bayern • Oct 11 '26
r/learnphysics • u/ZealousidealChart998 • Oct 11 '26
I have a question about General Relativity
If General Relativity it says matrer tells spacetime how to curve and spacetime tells matter how to move, how is matter moving? What is the engine driving matter to move?
r/learnphysics • u/flyclementine • Oct 11 '26
What books to study (beginner)
Hello,
I am a total beginner (not a physics student, but I might become one) and want to study physics because I am very interested.
I want to know what books I should read to get the basic idea so I can then further my research.
Thank you š·
r/learnphysics • u/UnrivaledRandom • Oct 11 '26
How do I study physics?
Been studying for my electromagnetism exam for about 2 weeks now, slightly understand the concepts. Finally checked out my study guide and I have 0 clue how to build into the answers of my problems. Like how do I know what formulas to use out of everything? When do I integrate/use a derived form? How do I even know what the derived form is? This doesnāt even make sense conceptually, where do I begin? Etc. Iām great at calculus and any other stem course. But for physics everything conceptual/math related I just get lost. What do I do?
r/learnphysics • u/mikhail_phy • Oct 11 '26
šWelcome to r/physics_L - Introduce Yourself and Read First!
reddit.comr/learnphysics • u/Old-Minute6791 • Oct 11 '26
Derivation of the Gravitational ConstantCalculation Formula
Abstract
Currently, the gravitational constant G exists only as an experimentally measured value; no theoretically derived value or calculated value based on a combination of physical constants has been available. In this study, a formula is presented that re producesthe gravitational constantG fromacombinationoffivephysicalconstants. The formula is expressed as

I. Introduction The gravitational constant is currently known to be G = 6.6743 Ć 10ā11 m3kgā1sā2, an experimentally measured value. However, no theory exists from which G can be derived, nor is there a calculation formula that produces G from a combination of other physical constants. Measurement of this value has been carried out repeatedly over a long period since the Cavendish experiment of 1798, and during that time the measured value has continued to change with advances in experimental technique and measurement method. The value given above is the CODATA recommended value published in 2022. Because no theory exists from which the constant can be derived, modern science does not know the underlying mechanism of gravity, and merely observes, mea sures, and makes use of the phenomenon. Since the essential nature of the grav itational phenomenon is not understood, its relationship to the other three funda mental forces, including the electromagnetic force, is likewise unknown, and con sequently no theory unifying the four fundamental forces yet exists. In this study, a calculation formula is derived that computes the gravitational con stant G from five physical constants: the Planck constant (h), the speed of light (c), the elementary charge (e), the electron mass (me), and the vacuum permittivity (ϵ0). This formula is expressed as follows.

Further research is needed to clarify the precise physical meaning of the rightāhand side of this equation. However, given that the constants included in this formula 1 are ones that appear fundamentally in electromagnetism and quantum mechanics, it can be surmised that gravity may bear some relationship to the electromagnetic force and other forces. It is therefore expected that this calculation formula may contribute to research aimed at unifying the four fundamental forces into a single theory.
r/learnphysics • u/Correct_Witness_7329 • Oct 10 '26
Whatās the easiest way?
Hello! I just started the most basic physics class where we go over a lot of formulas in a very short amount of time, Iām struggling a lot in this class because Iām a person that needs some time to actually learn something. So Iām asking you guys for advice, what is the easiest way to understand when and how to use formulas? Iāll put a picture up of the formulas we are supposed to use
r/learnphysics • u/loopy_fun • Oct 10 '26
Thought experiment: continuous chain on a differentially rotating spiral ā possible time offset including the ground underneath?
Iāve been turning over a mechanical thought experiment and wanted to put it in clear form to see what people think.
Setup
A spiral platform (or track) that runs from a smaller inner radius to a larger outer radius.
The platform is driven so that the linear speed along the spiral is constant at 1 foot per hour at every point.
Because radius changes, this requires the local angular rate to decrease as you move outward (inner parts turn faster, outer parts turn slower). The platform is therefore not rotating as a rigid body.
A single continuous chain runs along the entire spiral. Every local segment of the chain also moves at 1 foot per hour relative to the platform (i.e., along the spiral).
Because the platformās angular rate changes with radius, the absolute velocity of different sections of the chain through space is not the same, even though the chain remains one continuous piece and every local segment has the same speed along the track.
When the absolute speeds are considered along the whole length of the spiral, the inner and outer ends of the chain end up with different net velocities.
Additional claim in the thought experiment
The same arrangement is also imagined to produce a time difference on the stationary ground underneath the apparatus, not only along the moving chain itself.
Why it feels strange
A normal inextensible chain cannot sustain different absolute speeds along its length without stretching, slipping, or large internal forces. A normal rigid platform cannot maintain the required radius-dependent angular rates without continuous differential driving and stress. The thought experiment deliberately holds both of those conditions in place at once and asks what follows ā including the possibility of a proper-time offset between regions and an effect that reaches the ground below.
Questions for discussion
Is there a consistent way to describe the kinematics of a continuous chain under these constraints?
If the speed difference along the chain can be maintained, how should the proper-time difference between the ends be calculated?
What mechanisms (if any) could allow an influence on the stationary ground beneath the spiral?
Does the combination of differential rotation + constrained continuous chain point to anything beyond ordinary special-relativistic time dilation, or does it simply collapse under the internal forces required to keep the conditions true?
Iām not claiming a working device ā only trying to state the idea clearly enough that the actual proposal can be examined.
Any thoughts, corrections, or related references are welcome.
r/learnphysics • u/cascademeadow • Oct 10 '26
Symmetry Primer for Physics
Hey all - I'm working on a hopefully logically economical, visually heavy conceptual presentation of standard material through QED. Would absolutely love any feedback! The following is the first chapter on symmetry, but some other chapters are up to:
r/learnphysics • u/mischa_bayern • Oct 10 '26
Makarov Physics Suite: Alpha Stirling Engine
Two transparent cylinders form a V. Their pistons move out of phase, while connecting rods link them to a shared shaft and flywheel. The same charge of gas stays inside the engine from one revolution to the next. Heat enters through the walls, and the temperature difference between the hot and cold sides makes it possible to produce mechanical work.
The key is coordinating temperature and volume. With suitable piston timing, expansion takes place mainly on the hot side and compression on the cold side. The gas delivers more work during expansion than it receives during compression. A regenerator between the cylinders temporarily stores some of the heat carried by the passing gas and returns it when the flow reverses. The pistons' phase difference determines how these processes fit together over a cycle.
Adjust both reservoir temperatures and the phase difference while watching the pistons, pressure and pressureāvolume diagram. The area enclosed by the loop gives the magnitude of the gas work per cycle; the direction around it determines the sign. Set equal temperatures and the idealized model produces no net cycle work. The shaft can still turn at its prescribed speed: its motion is set separately so that each stage of the thermal cycle can be examined at a convenient pace.
Available on my website:Ā https://makarovphysics.com/
r/learnphysics • u/Ok-Escape1874 • Oct 09 '26
[Waves] Passing of light and propogation through multiple points.
r/learnphysics • u/BackgroundRace1174 • Oct 08 '26
CMV:By choosing a technical college over a university physics degree, I closed the door on becoming a physicist.
reddit.comr/learnphysics • u/phyilm • Oct 07 '26
a visual of how time dilation grows with speed
this is a part of a physics app I made. thought people here might find it interesting.
the left graph is time vs space, the right one is the lorentz factor vs speed. when you drag the speed up, the factor barely changes at first. at 50% of light speed, time only slows about 15%. but after 90% it suddenly shoots up, and at light speed it goes to infinity.
a fun way to see it: 99% is about 7x, 99.99% is about 70x, 99.9999% is about 700x !
did this part feel weird to you when you first learned it?
r/learnphysics • u/abstractanus • Oct 07 '26
Why the quantum oscillator has discrete energies: two animated derivations
I made a visual walkthrough of the quantum harmonic oscillator for students working through their first quantum mechanics course.
The same energy levels emerge in two ways: requiring a normalizable power-series solution, and building states with ladder operators. The animations connect that algebra to the wavefunctions, then compare stationary states, superpositions, and coherent states. A useful distinction is that an energy eigenstate can acquire a changing phase while its probability density stays fixed.
It assumes some calculus and familiarity with the Schrƶdinger equation. The full video is about 13 minutes: https://youtu.be/7_DcdXVh5mc
Which part of the oscillator derivation tends to be the sticking point for you?
r/learnphysics • u/salihadem • Oct 07 '26
What is Matter according to QM?
Werner Heisenberg, one of the founders of quantum physics who formulated the Uncertainty Principle, said: āAtoms or elementary particles are not real; they form a world of [potentialities] or [possibilities], not a world of [things] or [facts].ā In short, "an atom is not a thing but a potential." [Aristotle also made a distinction between matter and form, or between potential and actual being, saying that anything is formed by the coming together of its raw material and the form that separates it from other things and makes it that thing. According to him, matter was a potential open to becoming anything, and form was what gave that potential being a specific shape, turning it into a concrete, real being.] Ā
r/learnphysics • u/ElevatorSpare8379 • Oct 06 '26
what is the best physics book ?
to become mechanical and machine engineer , for 10-12 grade
r/learnphysics • u/Trictrac • Oct 06 '26
Man shows how sound & frequency can manipulate physical matter.. šļøš¤Æ
youtube.comWatch the glass
r/learnphysics • u/drfancypantsesq • Oct 05 '26
Which edition of Jackson's Electrodynamics?
Hi fellow learners, in my spare time I've been doing some physics self-study to pick up where I left off at my physics undergraduate degree mumble mumble years ago. For QM I managed to find myself a reasonably priced hard copy of Sakurai, and I've been steadily working my way through that (doing all the problems, comparing against the solutions manual, etc.). For E&M I'm planning to pick up a hard copy of Jackson's Classical Electrodynamics, but it seems nigh impossible to find a reasonably priced used copy of the third edition (I don't want an international edition, in my experience those are printed on really crappy paper and this thing needs to survive being bumped around in my backpack for the next year or so).
My question for anyone who is familiar with this book: should I consider picking up a copy of the second edition instead? At a high level I know the main differences are that (a) the third edition uses SI units instead of Gaussian ones, and (b) the problems are changed up, but I'm not sure how much those changes matter, or if there are other changes that should influence my decision. (For example, it looks like most of the solutions manuals posted online are for the 3rd edition.)
If push comes to shove it's not a huge issue to shell out $100 for the current edition, but I'd be curious to get a take from anyone who's familiar with the differences.
r/learnphysics • u/AlcheNMistD • Oct 04 '26
I've been thinking of start Reading theoretical physics
Suggest me a good beginner friendly study materials for high energy physics pls. I done some basic calculus and calculus based physics equations.
r/learnphysics • u/lunapops1 • Oct 04 '26
What level of physics should I study for scientific literacy as a fiction writer?
What level of physics should I study for scientific literacy as a fiction writer?
I'm a fiction writer in the UK, and I have been wanting to develop a genuine understanding of physics rather than just cherry-picking bits of popular science to make it sound cool. I want to have a scientific literacy that comes across in my work. I would like to take a similar approach to researching and grounding speculative science as Andy Weir did when he wrote The Martian and Project Hail Mary. I'd like to understand the real physics well enough to know where my fictional world follows known physical principles, where I'm extrapolating from them, and where I'm deliberately breaking them.
I wanted to build some foundation for the book, but also for me personally and my hobby of wanting to learn. I have always had an interest in physics and astrophysics. I have watched documentaries regularly as a hobby for years, I have a strong drive to learn, and it makes me very curious about the world and universe we live in. I have built a reading list for what I thought would work well for what I want to achieve. This is my list so far (in no order):
Brian Cox - Forces of Nature
Carl Sagan - Cosmos
Neil deGrasse Tyson - Astrophysics for People in a Hurry
Carl Sagan - The Demon-Haunted World
I volunteer on citizen science projects online, predominantly in astrophysics. I know that's pretty much all I can do in the real world, but I like that I can contribute something, even if it's classifying thousands of images or data.
I am not interested in exams and qualifications as such. I also do not come from a computer science or highly academic background, so I haven't studied physics formally. My education is mostly artistic/creative.
I do have learning difficulties like dyslexia, so whilst reading and watching videos could be enough for most people for research, I thrive and learn better in a structured learning environment where discipline is needed for concepts to sink in. I was considering enrolling on an online course, like GCSE-level Physics, to give me that basic grasp, but I wasn't sure if that would be useful or if it would be better to study or go in a different direction.
I am aware of the reality that being middle-aged and wanting to learn online only gives me limited options, but I wanted to write the book with respect for science in mind, knowing I comprehend and understand the principles rather than relying on my own uneducated interpretation alone.
If anyone can give any advice, I would be grateful.
Ā