Questions tagged [laws-of-physics]

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4
votes
4answers
656 views

How to know if the error is in a law or in uncertainty of the measurement?

I read these words in a (great) answer to this question: There are errors that come from measuring the quantities and errors that come from the inaccuracy of the laws themselves But how do we know ...
11
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6answers
2k views

Accuracy of physics laws

How accurate are physics laws? For example, for newtons' first law $F=ma$, if we can get a measurement of both force, mass and acceleration with a percentage of uncertainly close to $1\times 10^{-9}\%$...
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2answers
85 views

Is there a concept that refers to the fact that we understand systems, but we don't understand what's between those systems? [closed]

Is there a concept that refers to the fact that we understand systems, but we don't understand what's between those systems? By that I mean, we understand quantum mechanics, but if we keep asking the ...
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0answers
19 views

Is there any inflationary model or any string theory model that does not assume any symmetries as fundamental?

If I understand them right, in usual chaotic inflationary models or in string theory some symmetries are assumed as fundamental and therefore some fundamental laws of physics are assumed. But, in some ...
1
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1answer
57 views

Do we have any example of fundamental forces not working or having errors? [closed]

When we read about DNA, we see that the laws of chemistry and biochemistry and biology are rigid. But once in a while these laws fail to act (correct me if I'm wrong) and that is the source of what we ...
5
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4answers
694 views

What is the role of the laws of physics in a block universe?

Definition of a block universe - The idea that the whole universe exists simultaneously and time doesn’t flow. For those who favor this kind of theory (the few of you), what is the role of the laws of ...
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2answers
83 views

How do scientists derive equations and formulas? [closed]

How do scientists derive equations? For example, how do they know that: Work done = Force × Displacement And why is it always multiplication and not anything else? Why not addition?
2
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1answer
26 views

Are circular waves on a lake just the borders of a “bubble”?

When you throw a rock on a lake it makes circular visible waves. Can it be that the rock causes a “expansive bubble” underwater that we can only see its borders on the surface? Like the bubble made of ...
2
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2answers
69 views

“Law without law” in inflation?

John Wheeler proposed that the fundamental laws of physics actually were emergent from a primordial random/chaotic underlying state. According to this view, every physical law is actually emergent. Is ...
1
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0answers
55 views

Could the laws of physics have existed before the universe? [closed]

Alexander Vilenkin writes that perhaps the laws of physics could have existed even before the universe emerged from nothing. How could the laws of physics exist without the existence of the universe ...
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3answers
472 views

How to understand the laws of physics correctly? [closed]

Are the laws of physics something that exists separately from the universe or is it a description of the physical properties of the universe and objects in it?
3
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3answers
103 views

Why are there two pressures acting on a body in opposite direction during free fall on earth?

This is how my sir explained this to me: There are more than billions of atoms present in the earth's atmosphere. All those atoms have their force acting downwards. When he explained this diagram to ...
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0answers
16 views

Are the different fields in multi-field inflation described by different Lagrangians?

The most simple models of cosmological inflation consider only one scalar field. However, there are more complex models (like hybrid inflation or multi-field inflation) which consider more than one ...
2
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0answers
56 views

Could some kind of vacuum decay modify the most fundamental laws of physics?

A false vacuum is a hypothetical vacuum that is not actively decaying, but somewhat yet not entirely stable ("metastable"). It may last for a very long time in that state, and might ...
1
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4answers
108 views

Do the laws of physics describe the properties of the universe? [closed]

What do the laws of physics describe? Do they describe the properties of the universe? Or does the properties of the universe described by physical theories, and laws describe how those theories work?
12
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7answers
3k views

How does the whole universe agree on the laws of physics? [duplicate]

How is it possible that the every particle in the universe agrees on the laws of physics? What enforces those laws? Might the laws change slightly across the universe in the same way the cosmic ...
5
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1answer
106 views

What would it mean if symmetries are not fundamental at all?

In this paper 1 written by Joseph Polchinski, he seems to indicate that all symmetries of nature may not be fundamental: From more theoretical points of view, string theory appears to allow no exact ...
27
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5answers
6k views

General relativity (and other theories) when proven wrong

So, I have been watching some science videos regarding Einstein's theory on general relativity and until today the predictions based on his equations have been proven to stand. My question would be, ...
0
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0answers
19 views

Church–Turing–Deutsch principle

In what sense from the  Church–Turing–Deutsch follows that it is possible to simulate with one physical system all the other physical systems? I know that we can build logic circuits with a Toffoli ...
3
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2answers
102 views

Could the basic fundamental laws of physics change between universes in cosmological inflationary models?

According to cosmological inflationary models, different universes governed by different effective/low-energy laws of physics could exist, but the most fundamental laws of nature would remain the same....
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1answer
66 views

When an object is on an inclined plane the perpendicular gravitational component is equal to the normal force. How can you conclude this?

When an object is on an inclined plane the force of gravity acts downwards on the object and the normal force is perpendicular to the surface of the inclined plane. When we normally solve these ...
0
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2answers
32 views

Forces acting on two blocks of different masses and their relations (Newton's Laws)

Could someone please help me with this question about Newton's laws and free body diagram? "A block of mass M = 8.00 kg is located on a horizontal surface without friction. A second block of mass ...
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1answer
24 views

Binnig's fractal evolution applied to multiple universes?

Gerd Binnig, Nobel laureate in physics in 1986, proposed in his article "The fractal structure of evolution" 1 that everything in the universe, including its laws, had changed and became ...
3
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4answers
266 views

Why does a physical theory need to be testable? [closed]

We are generally not interested in physical theories that cannot be tested with the scientific method. This would seemingly apply even if the theory has other advantages, e.g. simpler, more general, ...
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3answers
134 views

Doesn't the Ideal Gas Law contradict the First Law of Thermodynamics

Let's say that an ideal gas does work on a piston, thus increasing the volume of the gas in its insulated cylinder. The pressure of the gas is assumed to be constant; therefore, by the ideal gas law, $...
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2answers
52 views

Force exerted by hand

Kindly give me the explanation of this numerical which says A ball of mass $0.2$ kg is thrown vertically upwards by applying a force by hand. If the hand moves $0.2$ m while applying the force and the ...
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0answers
93 views

Why are so many physical laws expressed in terms of *integer* powers of some quantities? [duplicate]

Why are so many fundamental physical laws expressed in terms of integer powers of some quantities? I'd expect this to be a very, very unlikely occorrance, since the Nature doesn't know that "we ...
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0answers
30 views

Unification of Forces

I was reading that unification of Forces is the most important task in the entirety of Physics. My question is why do the forces have to Unified. Why can't they be different forces what makes us think ...
3
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0answers
82 views

Why are most physical laws dependent on small powers?

The equation with the highest exponent I could find was the coefficient of energy loss of light scattered in an optical fiber: $$ {\displaystyle \alpha _{\text{scat}}={\frac {8\pi ^{3}}{3\lambda ^{4}}}...
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0answers
41 views

Are the laws of physics eternal? [duplicate]

It is scientifically assumed that objects on a planet or heavy bodies fall towards it, when not supported by some ground; irrespective of time. Over a million years this does not change. Its the same ...
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0answers
29 views

Consistency in the laws of physics [duplicate]

When I read about past events in the universe (i.e. big bang, formation of the sun and planets, etc) future events (i.e. sun becoming a red giant) and distant objects (black holes, nebulas, galaxies, ...
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0answers
49 views

Why are squares, square-roots, and second-order differentials, common in natural laws, but not cubes, cube-roots, and higher order effects? [duplicate]

Natural laws often feature squares and square roots, and second-order differential equations. Cubic laws, cube-roots, and third-order differentials are fairly rare. (Some counter-examples: square-...
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2answers
64 views

A Newton's third law confusion

Suppose you have a bird inside of a glass cage with some amount of gas inside it. We now place this cage on a weighing scale and observe its readings in different situations. Case (1): when the bird ...
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2answers
80 views

Explain how scaling of the inverse square law breaks down at a stars surface

If the radiation pressure at distance $d>R$ from the center of an isotropic black body star is found to be $$P_{rad}=\large{\frac{4\sigma T^4}{3c}}\left[1-\left(1-\frac{R^2}{d^2}\right)^{\frac{3}{2}...
5
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1answer
189 views

Laws of Physics [closed]

Here is a thought. Let us assume the there is an infinite uni-directional line of balls. And it is being jumbled up again and again, randomly. (say by 'God'!) I in my limited experience/capacity can ...
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2answers
108 views

Is there any different model for universe which can create life?

We know, our universe has four forces (there can be more than four) and some laws. And laws, forces, and particles consequently give the universe the ability to produce living things. Can we create ...
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0answers
53 views

Are there any physics equations that involve exponents >= 5? [duplicate]

This might be a strange physics question, but I am curious about it. Are there any physics equations that involve exponents $\geq$ 5? There are plenty of equations with square exponents. Inverse ...
7
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3answers
460 views

Is Newton's third law a consequence of first and second law?

Refer to the diagram shown above Question Assume a system of two objects ($1$ and $2$) which are applying force on one another ($F_{12}$ and $F_{21}$), which can be zero, (read $F_{12}$ as force on ...
1
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3answers
179 views

Why transcendental terms in the laws of nature are dimensionless?

Through my years in nuclear engineering, it has always been the case that in physical relations, the arguments of transcendental functions, e.g., the exponential in the law of radioactive decay, $N=...
1
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3answers
155 views

The first postulate in special relativity

In Einstein's special relativity, there are two postulates: 1. the laws of physics are invariant in all inertial frames of references; and 2. the speed of light in a vacuum is the same for all ...
1
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1answer
62 views

What did Stephen Hawking mean with “not demanded by logic or physical principle”?

In his book, "The Grand Design", physicist Stephen Hawking said: "It appears that the fundamental numbers, and even the form, of the apparent laws of nature are not demanded by logic or physical ...
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2answers
127 views

What are laws in physics? [duplicate]

Many times a precise definition of something in physics is not available but yet there exist some rough definitions that guide us through. I need the same rough (if not precise) definition of physical ...
6
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3answers
372 views

Are there any physics formulas with high/large exponents? [closed]

Most physical laws seem to only have low integer exponents for their variables - in my experience I've never seen a physical law containing variables raised to a power greater than 3 or occasionally 4....
8
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1answer
255 views

How do we know the laws of physics remain the same in different dimensions?

Section on Wikipedia dealing with the possibility of different dimensions. When reading this section it feels like there's a giant elephant in the room that is not addressed. For example, here's a ...
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3answers
73 views

What is the necessity to universalise a law? [closed]

What are the necessary conditions or observations that are required for universalisation of a law? I am not good at English so by universalise I mean to claim something to be universal. So how can ...
3
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2answers
126 views

Are these Stephen Hawking's statements legitimate? [closed]

I am reading 'Brief Answers to the Big Questions' by Stephen Hawking and it seems to me that some of his statements are just hypotheses, but they are written in such a way that they 'sound' like they ...
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1answer
35 views

A circuit out of a ring in amper law paradox [closed]

Assuming that there is three line of circuit and our amper ring is surrounded just two circuit . According to amper law the magnitude of B is just related to the circuits in the ring . But here the ...
2
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3answers
877 views

Why we don't use Ampere's law to find the magnetic field due to a wire of finite length at its perpendicular bisector?

I know that finite length doesn't have symmetry and thus its hard to apply maths here but take the case of magnetic field of a wire of finite length at a distance r from axis of the wire exactly at ...
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0answers
25 views

Arranging objects by mass [closed]

I have n objects with different masses . Say mass of n1=m1, n2=m2 .... so on. I want to use concept of centrality in physics to arrange these objects in a field (computer simulation ) . Where object ...
0
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1answer
90 views

Are there other theories (apart from string theory) that combined with inflation, would produce universes with different laws?

In chaotic inflation, space would stop expanding in some points, creating hubble volumes that could experience different spontaneous symmetry breaking, which would result in different properties, such ...