Questions tagged [laws-of-physics]
DO NOT USE THIS TAG just because the question deals with a law of physics!
194 questions
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In a string telephone, is the following plausible? [closed]
[![corner***
strong text
***]1]1
Blockquote
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Is "voltage across an inductor" actually real, or a convenient engineer trick?
Recently in electricity and magnetism class I learned how to solve basic circuits with Faraday's Law. You can't really go wrong with it; define currents in branches, charges/voltages on capacitors, ...
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Why Pauli exclusion principle and not Pauli exclusion law? [duplicate]
Why is the Pauli exclusion principle called a principle and not a law?
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Mass/weight in 2 places at the same time
Though it may seem like it is not, this is a genuine question of which I cannot find the answer online. The situation of how the question arose may make it seem otherwise.
I monitor my weight every ...
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2
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The independence of friction on area of surfaces in contact
Why is it said that as long as the normal contact force remains the same or constant, the frictional force is independent of the area of the surfaces in contact?
Does it mean when the normal force ...
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141
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Acceleration on a system of two particles
Let's imagine we have a system of two particles. If we apply an external force to only one of the two particles where the external force is greater than the internal force, then due to internal forces,...
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What would the universe look like if it had undergone a false vacuum decay in the past?
Inspired by "if a metastable de Sitter space lasting for cosmological durations really is impossible in string theory, then dark energy needs to be explained in some other way, e.g. via ...
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Why does the ball in Galileo's double inclined plane experiment reach the same height?
Why does the ball in Galileo's double inclined plane experiment reach the same height? I know how to show it by energy conservation law but am unable to prove it by the equations of motion. Can anyone ...
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Is math really fundamental or would it not matter if physics did not depend on math? [closed]
Can you disprove this please because it's been bugging me and I don't know much about physics at all as I'm only in 10th grade. It's one of those weird thoughts but I would like confirmation to keep ...
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Tree falling without inertia while people stay suspended in air for a split second due to inertia
I recently saw a video ( watch it 0.5x speed ) of a slanted coconut tree on the bank of a river in India breaking due to the weight of the kids who climbed on it.
The tree seems to have broken near ...
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Why don't the net acceleration of the truck becomes zero after hitting the man? [closed]
Imagine, there is a truck of mass 'm' accelerating with an acceleration 'a', this means that the truck definately carries some force 'F'(let). Now, imagine the truck collides with a man standing ...
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Can we have laws of physics without any laws of conservation?
The famous physicist John Archibald Wheeler proposed that there were no fundamental laws and that eventually, at very high energies, they would be broken. He proposed this conjecture when it was ...
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Do symmetries indicate that laws of physics are invariant?
Concerning symmetry in fundamental physics, it is usually said that symmetry indicates that laws of physics are invariant independently of something
For example, time translational symmetry indicates ...
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Axiom $\equiv$ postulate? [duplicate]
Is there any difference between an axiom and a postulate?
I would say that while an axiom is any proposition fixed as true without premises in a theory, a postulate is (also according with its ...
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What if the universe was not uniform...?
In this popular science article, they say that if our universe resulted to be non-uniform (that is highly anisotropic and inhomogeneous) then the fundamental laws of physics could change from place to ...
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Entropy change in free expansion
In the textbook of thermodynamics by Zemansky, I came to free expansion. If $dQ=0$ (because there is no heat exchange between system and surroundings), entropy should be $0$ as $dS=dQ/T.$ Now, the ...
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Why can't we run the laws of physics backwards and forwards in time infinitely?
So assuming we know all the laws of physics in differential equation form, and I have an estimate for the current large scale state of the universe (whatever standard assumptions/data cosmologists use ...
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Physics formulas of the form $A \cdot x^r$ and $r$ not integer [closed]
For a math class I am looking for some examples from physics for formulas of the form
$$
f(x) = A \cdot x^r
$$
and $r$ non-integer.
There are many simple examples where $r$ is an integer, but I didn't ...
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Will it reach the speed of Light? [duplicate]
So, I was just wondering if in an isolated environment where there is no external force acting on the body and the body (with any mass) is pushed with a force such that it has a constant acceleration, ...
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Why does dimensional analysis work? I need a elementary reason [duplicate]
I understand this is a very elementary question, but I haven't been able to come up with any elementary reason why it should work.
Also, why should quantities in an exponential be dimensionless?
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Is there a rigorous definition of a law of physics? [closed]
Is there, in some physics or mathematics text, a rigorous definition of what a law of physics is? I have read many physics books and papers, and while they all talk about particular laws of physics (...
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Does Edward Witten propose that all symmetries are emergent? [closed]
Some authors (like Holger B Nielsen, Robert B Laughlin, David Pines, John Wheeler...) have proposed that all fundamental symmetries and laws of physics are not really fundamental but rather emergent.
...
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Regarding curl of electric field and Maxwell's laws
I have a doubt...
Electric field is the negative gradient of potential ...
But curl of vector functions that are a gradient of a scalar function is the zero vector.
Then how come Maxwell stated that $\...
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When can a "theorem" be raised to a "principle"? [duplicate]
I am taking a 3rd year course in analytical mechanics, taught by a professor of mathematical physics.
One of the important results of analytical mechanics is d'Alembert's principle. According to our ...
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Can I say Axioms of Quantum Mechanics instead of Postulates?
I have been attempting to clarify the difference between an axiom and a postulate, but I keep running into almost contradictory answers. Some will say they're equivalent, some will say a postulate ...
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Is there any theory of fundamental physics that proposes that there are no symmetries at a fundamental level and that they are all emergent?
Quantum gravity theories usually propose that global symmetries are not fundamental. Are there any theories that propose that all symmetries (Lorentz symmetry, gauge symmetry...) and therefore the ...
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Is thermodynamics a physical theory? [closed]
It looks like to me that whenever we need to describe something we start from observations which lead to a theory. All theories seem to rely on laws:
theory of classical mechanics
Newton's laws
...
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Why there are some the laws of phyiscs written for specific case? [closed]
I am a new physics self student. I noticed that the laws of phyiscs are written for specific case, for example Newton's second law (in Wikipedia page https://simple.wikipedia.org/wiki/Newton%...
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955
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Difference between laws and principles [duplicate]
What is the difference between laws (e.g., Newton's Laws, Boyle's Law) and principles (e.g., Principle of Least Action , Heisenberg Uncertainty Principle)? As far as I know, both break down to some ...
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Local nature of physical laws
All the laws in physics are local in nature and that's why their formulation follows differential equations. My doubt is whether the locality is a proven theorem or it is a postulate?
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Could there be some process or event that would make the universe to be Lorentz non-invariant?
As far as we know the universe is invariant under the Lorentz symmetry and does have many other fundamental symmetries from which we derive the fundamental laws of physics.
But could there be any ...
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Are there any mathematically conceivable arrangements of an indeterministic universe that are not physically possible?
Are there any mathematically conceivable arrangements of this universe (particularly ones that respect its mass-energy content) that cannot in principle be achieved through its evolution in accordance ...
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Are there any Big Bounce models where the laws of physics (even the most fundamental ones) would change between cycles?
Big Crunch-Big Bang models (usually called Big Bounce models or cosmological oscillatory models) are highly unlikely to happen due to the discovery of the accelerated expansion of the universe.
But ...
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Could somehow the fundamental laws and symmetries of physics change or be broken? [closed]
There are some theoretical processes (like vacuum decay in quantum field theory) that could change the physical constants of the universe. Similarly, in inflation theory, various models predict that ...
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Understanding this quote by Feynman
This might be more of a question on semantics and interpretation and if this doesn't meet community guidelines, feel free to let me know and I'll delete it.
It doesn't matter how beautiful your ...
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Is there any exact law in physics? [closed]
Even for maybe the most fascinating computation in physics, about anomalous magnetic moment of the electron, theoretical physics gives:
$$a = 0.001 159 652 164 ± 0.000 000 000 108$$
which is not "...
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What is the shortest form way to fully describe the way our universse functions? [closed]
Let's say we wanted to explain to some alien living in another universe with different laws of physics to how our universe worked, what is the shortest way of doing this?
A different way of looking at ...
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Is it possible to alter any of Newton's three laws without altering the other two? If yes what will be the consequences?
Is it possible to alter any of the newton's laws without altering the other two? (We call such a system as a non-newtonian system)
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Quantifiers in physical theories vs reality
I understand a physical theory as a set of axioms/postulates like an axiomatic system in mathematics. When we use some theory to describe the physical world we assume that the axioms hold. In other ...
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Am I correct in saying "falsifiability is the feature of a scientific theory to be tested"?
Falsifiability is usually defined as "the extent to which a scientific theory can be proven wrong". Does this mean that falsifiability is basically the extent to which a scientific theory is ...
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How exactly do physicists reject and accept theories/models in physics?
I'm curious about the rejection/acceptance of a theory/model in physics. Is the only criterion to accept a model/theory is the explanation of data? Or are there more criterions? For example, we still ...
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Measurement of force
According to Newton's Second Law,
$F=ma$
which is based on the fact that force is proportional to acceleration for a constant mass.
But how will someone measure force to confirm this?
Suppose one ...
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1
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Can postulates be proven wrong? [closed]
When Dalton gave his atomic theory, he postulated that atoms were the smallest indivisible part of matter. But now we know that they are composed of even smaller particles. So, the postulate has been ...
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What is a "fundamental law of nature"? [duplicate]
The trigger for this question is from "University Physics with Modern Physics" (by Young & Freedman) when they mentioned that Ohm's law is not actually a law; this sentiment was echoed ...
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How necessary are the laws of physics given the impossibility of violating the law of conservation?
The Damascene theologian Ibn Taymiyya believed that God originates things ex materia, not ex nihilo or without prior material conditions, arguing that this latter type of creation entails a logical ...
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Do all physical processes necessarily imply a computation is taking place? [closed]
I would like to understand if any and all physical processes taking place, necessarily imply computations are also taking place.
As a motivating scenario for the question, consider the following:
...
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About the tautology of physics quantities and laws [closed]
Physics quantities and laws, especially some fundamental laws and quantities, show property of tautology. For instance, mass and Newton's second law.
My question is why physics quantities and laws ...
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3
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Why does the national center for science education say “gravity is only a theory”? [closed]
I had someone show me that when you search “gravity is fact” on google you’ll get the National Center for Science Education saying things like “gravity is only a theory”
Can someone just read these ...
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Are Laws of nature independent of time? [duplicate]
There are certain laws that govern the universe and these laws make up the fundamentals of any physical observation. But were these laws present the way there are now since the beginning of space time,...
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How do we know that physical laws/postulates/principles/rules are true? [closed]
There are many principles in physics. Two examples are conservation of energy and Pauli exclusion principle.
How do we know that such principles are true? What if there occur exceptional events that ...
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