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Questions tagged [laws-of-physics]

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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 ...
DJFUNKYDOG's user avatar
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2 answers
44 views

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 ...
Shreya Murasing's user avatar
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2 answers
113 views

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,...
Mathologist's user avatar
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1 answer
189 views

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 ...
Allure's user avatar
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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 ...
Mathologist's user avatar
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92 views

All possible models to explain the hierarchy problem?

There is an interesting paper by Arkani-Hamed and collaborators (https://arxiv.org/abs/1607.06821) to address the hierarchy problem. There, they consider many possible models of fundamental particle ...
vengaq's user avatar
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1 answer
163 views

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 ...
Soha's user avatar
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3 votes
1 answer
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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 ...
wedneday's user avatar
-1 votes
1 answer
79 views

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 ...
Sushant Sinha's user avatar
9 votes
4 answers
1k views

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 ...
vengaq's user avatar
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1 answer
146 views

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 ...
vengaq's user avatar
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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 ...
anna's user avatar
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1 vote
1 answer
81 views

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 ...
vengaq's user avatar
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2 votes
3 answers
293 views

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 ...
Suhail Sarwar's user avatar
13 votes
4 answers
2k views

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 ...
Ameet Sharma's user avatar
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1 vote
1 answer
92 views

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 ...
Julia's user avatar
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0 answers
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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, ...
bm27's user avatar
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1 vote
2 answers
134 views

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?
Neeladri Reddy's user avatar
1 vote
3 answers
178 views

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 (...
1 vote
0 answers
82 views

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. ...
vengaq's user avatar
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0 votes
3 answers
201 views

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 $\...
Varsha's user avatar
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1 answer
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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 ...
Foxy's user avatar
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1 vote
3 answers
271 views

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 ...
one two's user avatar
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6 votes
4 answers
200 views

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 ...
vengaq's user avatar
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0 votes
3 answers
320 views

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 ...
Federico Gentile's user avatar
-2 votes
1 answer
125 views

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%...
Homam Hassn's user avatar
1 vote
2 answers
829 views

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 ...
quanity's user avatar
0 votes
1 answer
84 views

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?
rkn's user avatar
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1 vote
1 answer
92 views

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 ...
vengaq's user avatar
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0 votes
1 answer
98 views

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 ...
Mohammad Abu-Zidan's user avatar
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0 answers
60 views

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 ...
vengaq's user avatar
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-1 votes
2 answers
117 views

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 ...
vengaq's user avatar
  • 2,466
11 votes
6 answers
6k views

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 ...
Ambica Govind's user avatar
2 votes
3 answers
476 views

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 "...
moshtaba's user avatar
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0 votes
2 answers
77 views

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 ...
Jack's user avatar
  • 535
2 votes
1 answer
78 views

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)
KAMAL's user avatar
  • 21
0 votes
1 answer
100 views

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 ...
Anton's user avatar
  • 281
5 votes
3 answers
534 views

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 ...
Vedant Rana's user avatar
9 votes
6 answers
3k views

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 ...
Vedant Rana's user avatar
1 vote
3 answers
570 views

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 ...
Vedant Chhapariya's user avatar
0 votes
1 answer
212 views

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 ...
Dom Tesilbirth Shira's user avatar
0 votes
2 answers
243 views

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 ...
Tham's user avatar
  • 185
1 vote
1 answer
122 views

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 ...
Mohammad Abu-Zidan's user avatar
-1 votes
2 answers
120 views

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: ...
tamale's user avatar
  • 123
0 votes
2 answers
187 views

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 ...
XL _At_Here_There's user avatar
-3 votes
3 answers
1k views

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 ...
Beans's user avatar
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8 votes
7 answers
2k views

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,...
A.M.'s user avatar
  • 697
0 votes
3 answers
122 views

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 ...
Xfce4's user avatar
  • 720
3 votes
1 answer
241 views

Equations and functions in physics and mathematics

In physics we can define velocity as the derivative of position. We can write: $$u = \frac{d}{dt}x(t)$$ or $$u = g(t)$$ where $g$ denotes the function after differentation of the position with respect ...
Anton's user avatar
  • 281
11 votes
2 answers
1k views

Do Newton's laws of motion imply no physical difference between different inertial frames of reference?

I'm a mathematician learning physics from scratch, for my own curiosity and interest. Starting from the basics, I'm trying to get a deep grasp of Newton's laws of motion. V.I. Arnold describes Galileo'...
35T41's user avatar
  • 404