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.

learn more… | top users | synonyms

0
votes
1answer
199 views

What would it take for a physical phenomenon to be telekinetic?

I've just watched an episode by MinutePhysics called "Real World Telekinesis". In it, Neil Turok (I wonder if that is his actual name; I remember playing a game called "Turok: Dinosaur Hunter" on ...
0
votes
1answer
140 views

Why the kilogram is not defined? [duplicate]

Possible Duplicate: Why do we still not have an exact definition for a kilogram? I was thinking about SI units. I found the following definition for the base units: Meter: distance ...
0
votes
1answer
487 views

Wave packets v.s. wave trains

Could someone please explain the difference between a wave packet and a wave train? I have rummaged around online but have not been able to find a definitive definition.
0
votes
1answer
341 views

Energy versus free-energy diagram

Energy versus free energy diagram. I haven't been able to find an adequate definition of these two terms in relation to each other. Could someone point me in the right direction, please? From Borrell ...
0
votes
1answer
27 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 ...
0
votes
1answer
57 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 $B$. ...
0
votes
1answer
583 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 ...
0
votes
2answers
820 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?
0
votes
0answers
24 views

What do we mean by “ground” in an electrical circuit? [migrated]

What do we mean by ground in an electrical circuit? When we want to solve electrical circuits problems, we set a "ground" level which is mean that the potential on it equal to $0$. I wonder how the ...
0
votes
1answer
19 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 ...
0
votes
0answers
43 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 ...
0
votes
0answers
64 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 ...
0
votes
3answers
7k 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 ...
0
votes
5answers
173 views

Are events in this experiment simultaneous if observed in platform's frame?

In some contexts e.g. on wiki it is defined as a matter of happening . In others(e.g. as defined by Einstein in his book "Relativity the special and general theory") it is defined as a matter of ...
-1
votes
3answers
354 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
1answer
358 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
votes
1answer
124 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
132 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 ...