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-3
votes
0answers
18 views

Books for students [duplicate]

Can any one please suggest me books for physics. I need a book for good theory and concept . And a book for practice , it should contain some solved questions. The both the books should contain ...
34
votes
4answers
17k views

Why can't energy be created or destroyed?

My physics instructor told the class, when lecturing about energy, that it can't be created or destroyed. Why is that? Is there a theory or scientific evidence that proves his statement true or ...
10
votes
2answers
2k views

Hydrostatic friction: why do water droplets stay at rest on an inclined glass surface?

This is a non-expert question on a (seemingly simple) text-book topic. The question is about "hydrostatic friction", defined as follows. Consider a drop of water resting on a flat surface. If the ...
-1
votes
2answers
71 views

Are there any equations in physics that will always equal 1?

I am sorry to ask such a layman question but I am really interested if there are any equations in physics that will always equal one or that will always equal a number very close to one. If there are ...
9
votes
6answers
1k views

What is the physical definition of causality?

Maxwell's equations give a physical relationship between the electric and magnetic fields $\vec E$, $\vec B$ at the same time, which some interpret as changes in one causes changes in the other etc. I ...
3
votes
2answers
31 views

Current loop and direction ambiguity of the magnetic moment

Consider a circular loop in the XY-plane which carries a current $I$. Then it behaves as a magnetic dipole with moment $\textbf{m}=I\int d\textbf{S}$ where $\int d\textbf{S}$ is the area of the loop ...
0
votes
1answer
28 views

What is “unity constant form” and why is it useful?

I read the following in a tutorial: The standard transfer function of a first order system is: $$G(s) = \frac{k}{s + a}$$ Arranging this into unity constant form gives: $$G(s) = ...
5
votes
2answers
2k views

Why does a balloon spiral in air instead of moving in a straight line?

When an air-filled balloon is released without its opening tied up, it moves in a circular path rather than a straight line. Why is that? PS: I don't know what to tag this question as.
0
votes
0answers
20 views

Length of liquid in capillary tube

A long capillary tube with both ends open is filled with water and then set in a vertical position in air.What is the length of liquid column remaining in the tube ? Surface tension of water is ...
1
vote
0answers
66 views

A question about ultimate computation capability

If we consider the physical limit of computational capability of a system with average energy $E$, then (1) According to Margolus and Levitin, a quantum system with average energy $E$ takes time at ...
1
vote
2answers
57 views

Determine the height of a tall building with the aid of a barometer

I read a story in which an it was asked in an exam to show how it is possible to determine the height of a tall building with the aid of a barometer. This story is quite famous I guess, and the ...
0
votes
1answer
34 views

Tension in mass less string [closed]

I have encountered some problems where there is different tensions in a mass less string. How is this possible? A good example would be
16
votes
3answers
1k views

Accidental, unplanned breakthroughs in physics [closed]

There is possibly some idiom or saying like this, "If you try too hard for something, you will never get it. If you do not aim for something, it may fall on you accidentally, not as you originally ...
8
votes
4answers
433 views

What fundamental principles or theories are required by modern physics?

We have been taught that speed of light is insurmountable but as we know an experiment recently tried to show otherwise. If the experiment did turn out to be correct and confirmed by others, would ...
79
votes
18answers
11k views

Why do most formulas in physics have integer and rational exponents?

I mean, why is $F=ma$? Why not $m^{0.123}$, $a^{1.43}$ or some random non-integers or irrational? I hope you understand that my question isn't limited just to force, energy, velocity, etc.; it also ...
8
votes
7answers
11k views

Can a scientific theory ever be absolutely proven?

I personally cringe when people talk about scientific theories in the same way we talk about everyday theories. I was under the impression a scientific theory is similar to a mathematical proof; ...
-1
votes
1answer
160 views

Do Physics concepts build on top of other concepts?

I am taking a calculus based physics class and I am struggling. I am wondering if I do not understand some concepts, will I be unable to understand future concepts introduced in the same class? In ...
18
votes
11answers
57k views

How do you start learning physics by yourself? [closed]

I think this question has its place here because I am sure some of you are "self-taught experts" and can guide me a little through this process. Considering that : I don't have any physics scholar ...
1
vote
1answer
109 views

Learning Undergrad Physics [duplicate]

I am an undergrad physics student who has finished the first year curriculum: very basic mechanics and thermal physics; basic linear algebra; basic multivariable calculus and differential equations; ...
2
votes
3answers
29k views

Uses of vectors in real life [closed]

I always wonder how vectors are used in real life.Vectors and decomposition of vectors,dot and cross products are taught in the early stage in every undergraduate physics course and in every ...
1
vote
0answers
23 views

A modern version of Landau theoretical minimum? [duplicate]

Can anyone point to me any modern books that are similar to Landau's book in scope and depth, these books used to serve as the backbone that determines one’s level of scientific culture, and since ...
0
votes
3answers
150 views

The study of the physical universe [closed]

If physics is the study of the physical universe, wouldn't that mean chemistry, biology, neuroscience, zoology, history, economics, sociology, etc, wouldn't they all be subfields of physics? I believe ...
11
votes
7answers
2k views

Is physics rigorous in the mathematical sense?

I am a student studying Mathematics with no prior knowledge of Physics whatsoever except for very simple equations. I would like to ask, due to my experience with Mathematics: Is there a set of ...
2
votes
1answer
271 views

Question about two vehicles moving toward each other, but the answer doesn't seem correct, am I missing a key concept? [closed]

The problem statement Vehicle A and Vehicle B are moving in opposite directions on the NJTP. Vehicle A is heading south toward atlantic city while vehicle B is heading north towards Hoboken. In ...
2
votes
3answers
442 views

Can a theory be proven by an experiment (or series of) that sustains it?

This is a question that I've always had but it wasn't until the recent news regarding the BICEP2 experiment that I really gave thought about it (please note that the question is general and not ...
4
votes
2answers
106 views

Does physics have some division schema which divide physical amounts into these two classes?

Does physics have some division schema which divide amounts into these two classes? : A) amounts which can be counted by natural numbers (for example many units can be counted by number of ...
1
vote
5answers
338 views

Age of universe estimates

I was recently involved in a discussion on a sister site regarding how tightly coupled Physics is with the age of the Universe (and Earth). I believe that the Earth and the Universe are both billions ...
8
votes
3answers
5k views

Please recommend a good book about physics for young child (elementary school aged) [closed]

I'm looking for a book that would be appropriate for an advanced elementary school aged kids (say, 6-11 YO) describing the basics of physics (or sciences in general) in entertaining way. The ...
2
votes
2answers
1k views

The meaning of 'postulate' in physics? [duplicate]

What does postulate mean in physics? What is its role in physical theories? Is it possible to break physical postulates?
7
votes
2answers
17k views

Why do car keys have longer range when held next to your head?

I first saw this on Top Gear, and assumed it was a load of rubbish, but today I tried it out and it actually works, if you walk away from the car continuously unlocking/locking it until it stops, and ...
-2
votes
1answer
344 views

Is There a List of Physics Formulas? [closed]

I am looking for a list of simple physics formulas - like $F=ma$. Is there any website/book that is a list of such equations?
2
votes
1answer
169 views

Does physics address the topic of consciousness?

Does physics address the topic of consciousness? For instance, does physics say anything about how it might arise or what might be its qualitative properties? I'm wondering because it's interesting ...
5
votes
7answers
1k views

What are the frameworks of physics?

Are there physical theories in use, which don't fit into the frameworks of either Thermodynamics, Classical Mechanics (including General Relativity and the notion of classical fields) or Quantum ...
2
votes
5answers
708 views

Why mathematical equations can describe this world? [closed]

Since I want to understand the world, I learn physics from textbooks. But I feel there is a gap between the textbook and the world. I do not know why the equations in the textbook can control the ...
0
votes
2answers
563 views

General physics landau [duplicate]

I've found Landau 's book for a first course in physics (not theoretical physics, its title is general physics),the book is freely and legally avaible on archive.org ,but it's from 1967,is that ...
0
votes
0answers
79 views

What kind of physics topics exist? [duplicate]

The question says everything I want to know, but for more details: I enjoy studying physics but the problem is that I can't find any information with a summary of all physics topics, collected ...
2
votes
3answers
689 views

What does physics study? [closed]

Wikipedia definition: Physics (from Ancient Greek: φύσις physis "nature") is a natural science that involves the study of matter[1] and its motion through spacetime, along with related concepts such ...
1
vote
1answer
250 views

recommendation for a physics history/non-fiction book [closed]

I know that there are a lot theses being published on lives of physicists. Is there a history/non-fiction book that tracks the development of a problem chronologically? Like pieces of a puzzle. I ...
-1
votes
2answers
1k views

How to teach myself physics needed at undergraduate electrical engineer level? [closed]

I want to learn electrical engineering on my own, specifically because I'm interested in loudspeaker design, more specifically how to design active dipole loudspeakers using DSP crossovers. I have ...
3
votes
1answer
10k views

Is there any significance to 1.21 GW?

In connection with a related question on Science Fiction & Fantasy Stack Exchange page: does this number 1.21 GW make any sense? What is 1.21 GWatts? With what can you compare it? Can the ...
3
votes
1answer
4k views

Why does the monitor make a cracking noise?

After switching off the monitor, there's a single crack after a while. I wonder where exactly it comes from. I know that this is normal and not an indicator of being defect. This sound is also not ...
1
vote
0answers
132 views

Scales and Hooke's Law

Bob weighs $B$ kg and when he steps on a scale, the spring inside gets compressed by $c$ meters. Assuming the scale obeys Hooke's Law, if Alice weights $A$ kg, how much work is done compressing the ...
1
vote
1answer
102 views

Retarded field interaction

I was doing the following thought experiment: imagine a particle that moves at a certain velocity. Imagine also that the particle generates a field that propagates at velocity $v_f$. Well, if the ...
-1
votes
1answer
844 views

Percentage of water that is void or empty space?

At the atomic level, at sea level on earth, what percentage of normal pure drinking water is void or empty space? What percentage of lead (the kind used to insulate from nuclear radiation) is void or ...
2
votes
2answers
387 views

What's the meaning of dimensionality?

I got amazed with this answer and as you can see, I had a little talk with joriki. He suggested me some examples such as the 2DEG. I'm stuck with some aspects on dimensionality, see this line: A ...
0
votes
1answer
178 views

is there any difference between these Differential $dx^2$ and $(dx)^2$? [closed]

is there any difference between these Differential $dx^2$ and $(dx)^2$!? what is relation between them?
4
votes
1answer
631 views

interpretation of Green function

Is there a physical interpretation of the existence of poles for a Green function? In particular how can we interpret the fact that a pole is purely real or purely imaginary? It's a general question ...
1
vote
2answers
150 views

Weight on planet earth?

I was wondering : does the weight on the planet earth is equal over the years ? meaning : all the people , ground , water ,gas. does the weight stays the same over the years ?
1
vote
1answer
171 views

Why is it that when you pick up a cup from a stack of solo cups too quickly, they stick together?

Intuitively I think it makes sense but can somebody explain very clearly to a non-physics person why it is that when you pick up a cup from a stack of solo cups very quickly, the cup below it seems to ...