Questions tagged [laws-of-physics]
DO NOT USE THIS TAG just because the question deals with a law of physics!
191
questions
0
votes
2
answers
74
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,...
- 23
0
votes
1
answer
102
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 ...
- 19.7k
1
vote
0
answers
70
views
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 ...
- 23
0
votes
0
answers
89
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 ...
- 1,988
0
votes
1
answer
113
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 ...
- 17
3
votes
1
answer
93
views
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 ...
- 33
-1
votes
1
answer
76
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 ...
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 ...
- 1,988
0
votes
1
answer
138
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 ...
- 1,988
0
votes
1
answer
132
views
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 ...
- 361
1
vote
1
answer
69
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 ...
- 1,988
2
votes
3
answers
179
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 ...
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 ...
- 1,194
1
vote
1
answer
89
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 ...
- 1,682
0
votes
0
answers
34
views
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, ...
- 11
1
vote
2
answers
115
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?
- 410
1
vote
3
answers
150
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
68
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.
...
- 1,988
0
votes
3
answers
117
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 $\...
- 21
0
votes
1
answer
60
views
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 ...
- 113
1
vote
3
answers
216
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 ...
- 345
6
votes
4
answers
182
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 ...
- 1,988
0
votes
3
answers
232
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
...
- 251
-2
votes
1
answer
123
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%...
1
vote
2
answers
540
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 ...
- 1
0
votes
1
answer
81
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?
- 43
1
vote
1
answer
84
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 ...
- 1,988
0
votes
1
answer
94
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 ...
0
votes
0
answers
55
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 ...
- 1,988
-1
votes
2
answers
104
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 ...
- 1,988
11
votes
6
answers
5k
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 ...
- 1,590
2
votes
3
answers
409
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 "...
- 1,325
0
votes
2
answers
76
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 ...
- 477
2
votes
1
answer
70
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)
- 21
0
votes
1
answer
96
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 ...
- 281
5
votes
3
answers
497
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 ...
- 883
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 ...
- 883
1
vote
3
answers
474
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 ...
0
votes
1
answer
186
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 ...
0
votes
2
answers
216
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 ...
- 187
1
vote
1
answer
114
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 ...
-1
votes
2
answers
108
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:
...
- 123
0
votes
2
answers
172
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 ...
-3
votes
3
answers
871
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 ...
- 330
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,...
- 697
0
votes
3
answers
114
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 ...
- 720
3
votes
1
answer
218
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 ...
- 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'...
- 322
-4
votes
1
answer
183
views
Is below description of the difference between laws and principles of physics correct? [closed]
Could some one provide elaborated answer whether description of the difference between laws and principles of physics, which I found on the Internet
(https://sciencing.com/difference-between-law-and-...
- 386
0
votes
1
answer
165
views
What laws of physics suggest life and evolution will occur? [closed]
Do any laws of physics tell us why life and evolution occurs?
From my understanding the laws of physics is about reduction/materialism and with that we can explain everything else.
To that end, which ...
- 111