Links: Nature...

First Interstellar Asteroid Found]]>

Internal energy during the expansion of a gas?]]>

Update on liquid water on Mars - maybe it is sand?]]>

These are two conceptual questions we were given recently. It's strange how mathematically I regularly do much harder problems but these caught me out a bit

Q1.

If a one snooker ball hits another ball moving at constant speed,...

Force Questions -- Snooker ball collision and a rock through a window]]>

I would like your help understanding how to map a region of the space [itex] \mathbb{C}^2 [/itex] spanned by two complex conjugate variables to the real plane [itex] \mathbb{R}^2 [/itex] .

Specifically, let us think that we have two complex conugate variables [itex] z [/itex] and...

Map from space spanned by 2 complex conjugate vars to R^2]]>

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Area of triangle=(base x height)/2

a is the side of the triangle.

Area of an equilateral triangle: ##~\displaystyle...

Maximum-minimum area from a fixed length rope]]>

Verifying claims about backwards time travel]]>

Does black hole stop light or time?]]>

Will it retain its microscopic structure?

Why?

Does it have anything to do with zero point energy (I mean something like the lowest energy level of a quantum...

Extremely cold crystal]]>

However, if they are identical fermions, the...

2-particle Wavefunction and the Pauli Exclusion Principle]]>

Non engineer here trying to understand an engineering principle. I think I must be going wrong somewhere in my thought process.

1. Faraday tells us that the EMF generated in the secondary of a transformer is equal to the change in magnetic flux divided by the change in time.

2. The...

Magnetic flux in tap changing transformers]]>

I've been learning (the basic) of investing and one question I have is about when to start - in particular, when to put money into a retirement account?

If you've got debt (student loans) and minimal income (I work part-time,...

What Age Did You Put $ in Retirement Acct?]]>

the cyclic temperature profile leads to a time dependent density

using the mass conservation equation i.e....

Velocity in microchannel with temporal temperature variation]]>

I have been thinking about the Cavendish laboratory, Cambridge University, but I don't know whether it's open for visitors.]]>

*Motorcycle stator off an old Yam RD350 (known as RZ350 in the US) needs rewinding after some of the coils were "fried".

*The stator has 3 larger high voltage coils used for the CDI system - and is left...

Rewinding old 3-phase stator: Non-symmetrical layout]]>

Is it that I am missing something somewhere, but when I searched the ATLAS site to find out what experiments were planned to measure the self-interaction of the Higgs, I could see...

Measurements of the Self-Interaction of the Higgs]]>

In a superconducting ring does the contraction of space between electrons cause them to move inwards? Like in this animation.

In the proton frame of two parallel wires...

How To Consistently Explain Electromagnetism With Relativity]]>

Hi,

In the first question (question 4) in the attached file, how would you go about modelling the system and finding the equation of motion? All those masses are confusing me, I don't even know where to start.

I don't know whether the...

Vibrations - Modeling system, equation of motion]]>

Hi I was wondering if anyone could give me a hand with this problem I'm trying to solve.

I am trying to integrate this equation twice. I'm not really sure what to do with the right hand side of the equation.

Integration of equation relating to electrostatics]]>

If a particle is within 2 m/s of the speed of light (like at CERN) and then more energy is transferred to the particle, where does this energy go? Some sources I have read talk about relativistic mass getting bigger and approaching infinity as a particle approaches 'c'. However, this source...

Special Relativity & Relativistic Mass]]>

Asymptotic form of soliton-antisoliton solution for S.G eq.]]>

This thread is for showing your images of solar activity taken with YOUR cameras, telescopes etc.

That is, don't post images from SDO, SOHO or any other professional sources unless you specifically want to ask "how do they do that and what are those solar features I can see?

This...

Solar imaging and techniques]]>

Here's a fun thing to do on a Sunday. I was thinking of all the everyday objects that I no longer need as much or as often because I carry a smart phone. Because I'm old, I may prefer the older way of...

What Do Smart Phones (Partially) Replace?]]>

http://imagizer.imageshack.us/v2/800x600q90/690/2hpo.jpg [Broken]]]>

[tex] \Omega = -\frac{1}{2} Tr (-1)^{(2J_3)} (2J_3)^2 [/tex]

+

I don't understand how to use this formula. (By the way, the normalization is probably not the same for...

Question about Wall crossing formula]]>

Here is the last page of part 5.

https://www.physicsforums.com/threads/random-thoughts-part-5.851969/page-134]]>

Does anyone have any safety recommendation on how to build a Ruben's tube? What to do and what not to do?

Could the tube explode under the wrong circumstances? I am planning to use a steel tube. Maybe other metals are safer or better? The flammable gas is usually propane. Should I use a...

Ruben's Tube and Safety]]>

For my Grade 12 Physics ISU, basically I have to build a self-contained device (Can complete the task on its own after setting it up) using physics that can pick up an raw egg inside an egg cup and place safely it on a...

Egg Tower Project]]>

I have a problem understanding what happens when a plane electromagnetic wave hits a surface consisting of two medias of different optical density.

My old school litterature tells me two formulas which I really don't understand where they come from.

The same teacher starts by telling me...

Refraction formula confusion]]>

There are many different wave equations that describe different wave-like phenomena. Being a differential equation, the WE is a pointwise relation and applies to the wavefield at spatial points.

- The equation is
**homogeneous**when the source term is zero. That means that...

Homogeneous Wave Equation and its Solutions]]>

I ended up with this terrifying-looking thing:

View attachment 215464

So distributing, I ended up with:

View attachment 215465

Evaluating the second integral poses no...

Integral of Dirac function from 0 to a... value]]>

I'm opening this thread because actually I have difficulties in choosing my university.

Actually I'm at the last year of the high school, based on Science, it's called "Liceo Scientifico", you can Google...

How to choose a University]]>

Fusion power, still the king of power?]]>

Considering that two person has bot no experience for the work, a company prefer to hire younger people, or they care more about the skills a person have?

Thanks.]]>

Find the concentrations of all ions in the solution at equilibrium after 0.213 L of 0.433 M aqueous Cu(NO3)2 solution is mixed with 0.213 L of 0.120 M KOH solution. Ksp for Cu(OH)2 is 1.1E-15.

n=m/M...

Concentration of Ions at Equilibrium]]>

Can anyone please give me hard and interesting problems regarding fluid mechanics problems such as hydrostatic and air prssure bouyance force and Bernoullis equation(Bernoullis equation problems only for liquids)? I tried...

Difficuilt and/or interesting problems in fluid mechanics]]>

“Think of the wire as a horizontal cylinder. If you apply an electric field pointing to...

Why is the electric field in an ideal wire zero?]]>

Unelegant, Unnatural, Ugly BSM theme books]]>

The residents of a small planet have bored a hole straight through its center as part of a communications system. The hole has been filled with a tube and the air has been pumped out of the tube to virtually eliminate friction....

SHM Question - Don't know my mistake]]>

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To find the natural frequency of a uniform cantilever beam, the area moment of inertia, cross-sectional area and density are not given, everything else is given by the lab, our group got a...

Why am I not getting the correct natural frequency?]]>

I'm asking in general which is your favorite country and city to visit?

Or which country do you want to visit or to live in?]]>

I'm trying to plot a straight line for a bipolar junction transistor to find the room temperature, T, using my experimental results for the associated base-emitter voltage, ##{V}_{BE}## and collector current, ##I_C##. Here's the equation that I'm using:

$$ I_C = α_F {I}_{EO}...

Straight line plot of bipolar transistor - temperature?]]>

In order to create a good thread i'm going to summarize the main problem of my life here, to know if there are problem...

Should I leave Italy?]]>

The chancellor of the California Community Colleges system believes that students who are not majoring in math or science should not have to take intermediate algebra to earn an associate degree. California has the...

Should Algebra Be Required At Community Colleges?]]>

The magnetic moment of the muon, g, is predicted by the Standard Model, to be equal to 2 and a bit more, with the quantity that we look at being g-2. We have both experimental measurements and theoretical predictions that are close to each other to many significant digits,...

Muon g-2 as a constraint on new physics]]>

Central heating - available differential pressure]]>

I was curious, does this apply to all the neurons that for example, move my right hand? Are all the neurons in my fingers individually that long, starting at the spine...

Neuron lengths, sizes and quantity]]>

2 squares are chosen at random from a chess board.What is the chance that these 2 squares will share exactly 1 corner?

P=favourable possibilities/Total possibilities

Chess board probability]]>

Molecular Dynamics Simulation - How Do You Find Parameters?]]>

I have two points on Earth at each end of a great circle path, for which I know the length in km and direction in degrees True. Also I have the RA and DEC of an object in space as seen from one of the previous points. The RA and DEC come from the setting circles of a telescope...

Vectors in space]]>

- equal to ##R## or,

- not equal to ##R##

Suppose the two frames are inertial frames....

Little issue regarding physical states]]>

View attachment 215369

12)a)

a) Since both events are independent : P( 33) = 9 / 441

b) Let’s have

4: throwing 4

Not 4 : not throwing 4

P...

Probability of getting an ace in case of a loaded die]]>

View attachment 208002

The object above does not seem to have numbers in a definite pattern, so, I think that this object will not have a single equation that describes the object, but instead there will be multiple number of...

A single or multiple equations of 'y'?]]>

How are mathematical ideas discovered]]>

I often run into question which I have no idea how to answer, or where to find information. So I figured maybe it...

Hello Physics Forum!]]>

Methods of Trapping Laser Light]]>

I have to run a few algorithms using Python on PNG-images. However, I also know that PNG is compressed... How do I do this? I need to learn the following:

1: Extracting the RGB information about the pixels.

2: Isolating parts of the image (for example, importing an image and only working on...

Working with PNG images in Python]]>

Could we find enough mass to slow down the Earth's rotation?]]>

for example see following article:

http://dx.doi.org/10.1016/j.adt.2017.05.001]]>

Particle Physics:

- Griffiths: Introduction to Elementary Particles

- Thomson: Modern Particle Physics

- Nachtmann: Elementary Particle Physics

-...

Recommended books in HEP, QFT, QM, GR]]>

I was wondering about a bubble moving with constant velocity in a liquid, and how the motion affects the mass transfer. Since the viscosity of the gas is significantly smaller than the viscosity of the liquid, the condition ## \tau_{gas} = \tau_{liquid} ## tells me that

$$ \mu_{gas} (...

Higbie's penetration theory in a bubble]]>

Thank you.]]>

Given a generic reaction ## Reagents ↔ Products ## the velocity of the reaction is ##R = R_{right} - R_{left} ##

To take in account that the velocity of the reaction will slow if approaching the equilibrium we say that

$$ R = R_{right}(1 - \frac K K_{eq}) $$

Although it seems...

Chemical Kinetics: velocity and equilibrium]]>

To avoid confusion let’s move the clocks way out in space to a real inertial...

A tale of three clocks]]>

Hello, I am attempting to use the velocity Verlet algorithm of integration applied to the solar system in c++. My goal is be able to use the outputted position components in a plot to see if the trajectory of my object is...

Velocity Verlet applied to solar system with C++]]>

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A mass ##m## travels in a straight line with velocity ##v_0## perpendicular to a uniform stick of mass ##m## and length ##l##, which is initially at rest.. The distance from the center of mass of...

Elastic Collision between a Ball and a Stick]]>

View attachment 215494

I am not sure exactly what this question is asking for, especially in regards to the voltage drop. How would the graph of voltage drop vs Rmax-Rmin be any different to...

Voltage Drop PTC Thermistor]]>

I have an 'Earth and Space Science' topic test tomorrow.

Heavily revising, I come across a section that will be in the test: geothermal energy.

It works by cold water being pumped down in pipes, underground and then back up, hot, in form of steam to spin turbines and generate...

Where does the Earth's heat come from?]]>

linear polarizers: angle between electric-magnetic field]]>

This week, your photo can be on any subject. However, there is one very

Please note that if your...

PF Photo Contest - Technicolor (11/18-11/24)]]>

I'm an A-levels student right now, and I have a hard time deciding on my major after my course.

Right now, I have a focus on bioengineering, and my parents support this decision thinking I'll build an Ironman suit and cure cancer.

However, I want to know what is the field is actually like...

What is Bioengineering Like?]]>

thank you]]>

Thank you.]]>

I hope to be able to contribute to discussions surrounding power networks and electricity generation, and hopefully interest some of you guys in some probing discussions!

I currently work as an operator in a power station.]]>

Non-zero components of Riemann curvature tensor with Schwarzschild metric]]>

Recently, however, I got email notification for three threads that were spam. Two of them were already removed when I...

Is the security of PF at stake?]]>

My wife just drew this

View attachment 93241]]>

Not able to start new threads]]>

This may be a simple answer, but any help is appreciated.]]>

Fluid flow through a pipe constriction - what would you feel]]>

A single electron atom has the outer electron in a 4f1 excited state. Write down the orbital and spin angular momentum quantum numbers and the associated magnetic quantum numbers for this state.

I...

Orbital/Spin angular momentum + magnetic quantum numbers]]>

GW170608 - Another Binary Black Hole Merger Observed]]>

You know the correct term for rotational motion is the centripetal force and it is toward the centre. I have a problem with rotational equilibrium...

Explanation motorcycle leaning without centrifugal force?]]>

Stream inside paraffin oil when exposed to high volage]]>

Is it possible to have structures older than 500,000 years old]]>

Show that in the chiral (massless) limit, Gamma 5 commutes with the Dirac Hamiltonian in the presence of an electromagnetic field.

My first question is whether...

Commutator of the Dirac Hamiltonian and gamma 5]]>

A factory has gotten an order for ##N## products. For this job it has ##n## available machines.If all the machines would work simultaneously the order would have been completed in 24 hours. However due some complications there...

Work rate (word) problem]]>

How do I draw all forces on a stone sinking in water? And what are the names of the forces? And will the stone reach terminal velocity and be sinking in constant velocity?

In some websites they...

How do I draw all forces on a stone sinking in water?]]>