The definition tag is used in situations where the question is either about how some term or concept is define or where the validity of an answer depends on a subtle definition of some term or concept used in the question.

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2answers
19 views

How do we count beats?

Books say that one beat constitutes two successive maxima of sound intensity with a minima in between. This is confusing me as the definition of beat period says - it is the time interval between two ...
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2answers
33 views

What is the difference between the actual distance covered by a projected object and the displacement?

What is the difference between the actual distance covered by a projected object and the displacement? A stone was projected with an angle of projection of 30 and it covered a horizontal distance ...
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1answer
60 views

What is a conservative force?

Currently I have three different pictures to describe/understand conservative forces. For the moment I just want to get an electron from point A to point B. In the near surrounding is another electron ...
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1answer
3k views

Difference between angular frequency and angular velocity?

What is the difference between angular frequency and angular velocity? I think one is used for SHM and the other for circular motion? Also can both be used for centreptal accelartion? I think angular ...
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1answer
138 views

Determination of displacement value in work formula

A net force will always create displacement which approaches infinity if left undisturbed. So how to fix a value of displacement in work formula? Isn't a mention time interval necessary? Or do we ...
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1answer
114 views

The formula used to calculate electrical potential energy

Sorry for the ugly picture but it makes my question more understandable. The $\Delta V$ from $A$ to $B$ is calculated by$$\int_A^B E \, \mathrm{d}r$$ where $r$ is the distance between $A$ and $B$. ...
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1answer
2k views

Definition of “intensive” and “extensive” properties

Today I was asked what does it mean for a physical property of a system to be intensive. My first answer, loosely speaking, was: "It is a property that is local." I was specifically thinking ...
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2answers
2k views

How would you determine whether an object is at equilibrium? [closed]

How would you determine whether an object is at equilibrium or not? What is the definition of equilibrium?
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3answers
12k views

Difference b/w Kinetics & Kinematics w/concrete example

(I know whether I understand this or not doesn't matter much to my work & study but am just curious.) I still can't differentiate in my head kinetics and kinematics (similar thread is found but ...
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1answer
37 views

Mathematical misunderstanding of Work-Potential Energy Theorem?

This is a relatively basic question, but I don't understand why it is the case. This is from my dynamics book and is mainly a mathematical misunderstanding. $$ \ dU = F\cos\theta ds $$ Which means ...
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0answers
24 views

How is the octane percentage defined? [migrated]

Normally octane percentage is mentioned on petrol (95% octane). How is this defined? Is it percentage of chemical or some other parameters?
0
votes
1answer
48 views

What is many-body bound state?

Bound state by definition is a state when particles are bounded together, so then "many-body bound state" would be bound state for a system of many bodies. Then I have several puzzles: 1. is the state ...
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0answers
30 views

The relationship between the two statistical mechanical definitions of entropy

It seems like similar questions have been asked here; hopefully my question is not a duplicate. I am reading my textbook on the statistical mechanical definitions of entropy, and I am very confused ...
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votes
1answer
32 views

What does it mean by coherence between waves?

I know by definition, coherence is pair of waves that have constant phase difference. What does this mean? Does it mean they are always have a 360 degrees, or 0 degrees phase difference? Or could they ...
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votes
1answer
36 views

Variable definition in wave function for scattering particle?

For the wave function of a scattered particle when finding the scattering aptitude we have: $$\psi(r)=Ae^{ik_0∙r}+\frac{2\mu}{\hbar^2} ∫G(r-r')V(r')\psi(r')d^3r'$$ I was wondering what the variables ...
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votes
0answers
54 views

Equilibrium Condition

In classical thermodynamics, equilibrium conditions means maximum entropy for a closed state. However, people always talk about equilibrium for open systems as well. How can one say that an open ...
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votes
0answers
83 views

Streamlines tangent to velocity vector

As from the title, I'm not too sure how they are related. Definition is that streamlines are instantaneously tangential to the velocity vector of the field. Why would a streamline that shows direction ...
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votes
1answer
51 views

Definition of “destructive” interference of waves

What is the commonly accepted precise definition of "destructive" interference of waves. Does it mean: interference with complete cancellation or interference where the amplitude gets smaller ...
-1
votes
3answers
381 views

Are we crystals?

Can we say that we are crystals because just like crystals we are made up of very small unit (cell) making up almost the same shape (our body) everywhere.
-1
votes
3answers
891 views

Differences between wavefunction, probability and probability density?

I am trying to understand the differences between wavefunction, probability and probability density. There are different definitions on the internet. For example: ...
-1
votes
1answer
904 views

Definition of the complex wavenumber

My syllabus of electromagnetism defines the complex wavenumber as: $$k = \omega\sqrt{\epsilon\mu}$$ with $\epsilon$ the complex permittivity and $\mu$ the complex permeability. Thus $\epsilon$ and ...
-1
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1answer
46 views

Angular displacement after full rotation

I was wondering is why angular displacement isn't $0$ after $n$ full rotations?
-1
votes
1answer
135 views

Poles, wavefunctions, transmission

Why is it said that $\operatorname{sech}x$ (a transmission amplitude) has a simple pole on the imaginary axis?
-3
votes
2answers
155 views

Do physics laws really apply to anything? [closed]

My professor said that a law was stated and announced as a law because it happens in our everyday life. He gave us an example of Newton's 3 laws. He said that walking possess 3 laws of Newton's. Is ...