Random Thoughts part 4

Time to split the thread again.

Here is the link to the old thread. http://ift.tt/1z0karx

Random Thoughts part 4

Random Thoughts part 4

Japan Earthquake: nuclear plants part 2

Torsion pendulum in Cavendish experiment

1. The problem statement, all variables and given/known data
In the Cavendish experiment, the two small balls have mass m each and are connected by a light rigid rod with length L. The two large balls have mass M each and are separated by the same distance L. The torsion constant of the...

Torsion pendulum in Cavendish experiment

Torsion pendulum in Cavendish experiment

Algebra 2 and Trig textbooks

Hey PF, as my thread a week or two ago said I am currently planning on taking a college Calc and Analytic Geometry class with formal education only up to Geometry. I am very proficient in Geometry, good in algebra 1, have some experience in Trig and a little in Algebra 2. For this reason I was...

Algebra 2 and Trig textbooks

Algebra 2 and Trig textbooks

Continuity at a point implies continuity in the neighborhood

I claim that if a function ##f:\mathbb{R}\rightarrow\mathbb{R}## is continuous at a point ##a##, then there exists a ##\delta>0## and ##|h|<\frac{\delta}{2}## such that ##f## is also continuous in the ##h##-neighbourhood of ##a##.



Please advice if my proof as follows is correct.



Continuity at...



Continuity at a point implies continuity in the neighborhood

Continuity at a point implies continuity in the neighborhood

Is there any scope for an Electronics and Telecom Engineer?

I am from Electronics and Telecom Engineer.Most of us get placement in software industry which is not our core field. My straight forward question is there any scope for an Electronics and Telecom Engineer?



If yes,what are the options or career path so that I can remain stick to My core branch...



Is there any scope for an Electronics and Telecom Engineer?

Is there any scope for an Electronics and Telecom Engineer?

Problems with Capitalism?

Anyone have advise on how to learn languages?

I guess it is ok to post this here, in any case if it's not I guess the moderators will edit it.



I am trying to teach myself german, grammar and pronounciation stick to me very easily, however I am having trouble building vocabulary and getting fast at sentence building.



My native language is...



Anyone have advise on how to learn languages?

Anyone have advise on how to learn languages?

Can you answer this virtual photon paradox?

In order to get my head around virtual particles I've created the following question. Maybe some bright person can answer this. If I can answer this question I feel I would have the required understanding to explain virtual particles to other people.



In the diagram below, A is a...



Can you answer this virtual photon paradox?

Can you answer this virtual photon paradox?

Bandwidth Theorem

1. The problem statement, all variables and given/known data

Consider a propagating wavepacket with initial length ## L_{0}##. Use the bandwidth theorem to show that the minimum range of angular frequencies present in the wavepacket is approximately:

$$ \Delta{\omega}\approx...



Bandwidth Theorem

Bandwidth Theorem

QCD vs. Spatial Expansion

This thread involves a little general relativity and a little particle physics.



Observations indicate that space is expanding at an accelerated rate.



Given this would continue, even atomic nuclei should be torn apart leaving single particles, isolated from one another by causal horizons.



What...



QCD vs. Spatial Expansion

QCD vs. Spatial Expansion

Book/Books on elementary number theory

Hello all,



I probably should have posted this in a math forum but I don't know of any. Can anyone recommend a book/books on elementary number theory with exercises? My math background is not very strong with very little knowledge of set theory so it should be understood by me. We're covering...



Book/Books on elementary number theory

Book/Books on elementary number theory

Is it possible to stop time completely?

When I was in school, I learned only Newtonian physics. Recently I have discovered that what they taught me was wrong, that gravity is not a force, it doesn't occur simultaneously, blah, blah, blah



Anyway, based on my study of Einstein's relativity, I was wondering if it's possible to slow time...



Is it possible to stop time completely?

Is it possible to stop time completely?

Decoherence question

I would like to understand why is decoherence needed in QM.

As I understand decoherence models irreversibility.

But if two quantum systems interact and resulting states are going in different directions they can't produce interference, right? Even if they do not interact with environment. So...



Decoherence question

Decoherence question

Fortran Complex Exponential

Hi, so I need to write a fortran code with 2, 2x2 matrices.



These matrices are in the form of B=(1 exp(i)(theta) 0 0) and D=(0 0 exp(i)(theta) 1) where i is sqrt of -1 and theta is an angle between 0 and 2pi.



I've expanded the exponential so it reads cos(theta)+isin(theta) and let theta=pi/2...



Fortran Complex Exponential

Fortran Complex Exponential

Solar System Origin

Dear All,





I understand that one of the most popular theories concerning the origin of the solar system begins with cloud of gas and dust (called a nebula), assumed to be the remnants of a supernova; in order to explain elements such as iron and above.





That this nebula begins to flatten into...



Solar System Origin

Solar System Origin

Is my blue the same as your blue ?

Hi All,



Is my blue the same as your blue ? and why ?



Thanks

Is my blue the same as your blue ?

What is the magnetic force on the particle

1. The problem statement, all variables and given/known data

A particle of mass M and charge Q>0 moves in a region of space where the magnetic field has a constant magnitude B and a downward direction. What is the magnetic force on the particle at an instant when it is moving...



What is the magnetic force on the particle

What is the magnetic force on the particle

What is the latest gossip on science

What is the latest gossip on science in general

What is the latest gossip on science