Conside the fig below. A tank of water (height of water column B) is kept on a electronic weighing scale . a metal cube (side a and density D) is hung from a spring balance and the spring balance is slowly lowered into the tank...

Force on the bottom of the vessel containing a submerged bod]]>

A University of Geneva researcher has recently shown that the accelerating expansion of the universe and the movement of the stars in the galaxies can be explained without drawing on the concepts of dark matter and dark...

Scale invariance of space]]>

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

I'm asked to find the P (T < ?? ) , v= 26 ,

2. Relevant equations

From the table , we could notice that P (T

t- distribution comfusion]]>

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

A tale of three clocks]]>

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

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

1) Would current flow, and if so, what would the flow of electrons look like?

2) How would the magnetic field look? (I imagine that if there was an electric current flowing, that the magnetic field would look a little like...

Magnetic Field of an AA Battery 'Immersed' in a Conductor]]>

Verifying claims about backwards time travel]]>

Mathematical Quantum Field Theory - Phase Space

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...

Mathematical Quantum Field Theory - Phase Space - Comments]]>

My question is that why is the negative charge on the oxygen atom with the single bond, why not on the oxygen atom with the double bond? I am confused.

Source: https://chem-net.blogspot.in/2012/01/simple-procedure-for-writing-lewis.html]]>

However , in the following question , i dont know how to identify whether the standard deviation given is standard deviation of sample or standard deviation of population ...... Can anyone...

standard deviation]]>

I was doing the derivation of the Lagrange equation of motion and had to do some calculus of variations.

The first step in the derivation is to multiply the integral of ƒ(y(x),y'(x);x)dx from x1 to x2 by δ.

and then by the chain rule we proceed. But I cannot understand why we are...

Delta x in the derivation of Lagrange equation]]>

Generalized Product Rule D^(n-m) (x^2 -1)^n (LaTeX inside)]]>

1.

why is it easier to make the wheels slipping if you rev the engine and relase the clutch fast (this from a standstill start)?

exampel; I can be in first gear and have full throttle and no slip will oucure in my car with low...

Why tires slips easier from a standstill start?]]>

A second harmonic standing wave has the known quantities of Amplitude (max y at antinode) A, maximum velocity (y=0 at antinode) v, string length L, tension in the string T.

Given that we know that it is second harmonic, we can...

Mass of a vibrating string]]>

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?]]>

A crucial insight from that article is that, when a wheel rolls along a flat surface, its axis...

A perfectly stiff wheel cannot roll on a stiff floor?]]>

A grindstone is used to sharpen knives and consists of a stone cylinder and a central axle There are bearings between the axle and the frame to reduce any friction.

This grindstone has a mass of 60 kg, a diameter of 0.600 m and...

Rotational Dynamics of a grindstone]]>

I am running a program that takes relatively long time to read the corpus of some documents, and create the topic model. The code to do this is:

Code (Text):

from gensim import models, corpora

corpus = corpora.BleiCorpus('./data/ap/ap.dat', './data/ap/vocab.txt')

#Creating the topic model...

corpus = corpora.BleiCorpus('./data/ap/ap.dat', './data/ap/vocab.txt')

#Creating the topic model...

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?]]>

Thank you.]]>

Collatz Conjecture]]>

We also know that, our Sun's spectrum is blackbody like, while a...

How to approach blackbody]]>

Use of the Radon transform on an ill-posed matrix]]>

I tried to open the top, but I couldn't - it wouldn't budge at all.

Then I shook the jar - so the sauce inside moved around.

I tried again and I effortless opened the jar.

Now - this got me thinking, why when I shook the jar did it open easily?

prior to...

Opening a top on a jar]]>

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.]]>

The question below is asking how long it would take for the cooler side of the handle to heat up till its unbearably hot.

View attachment 215103

I'm having a bit of trouble trying to understand the solution and would like...

Fourier Conduction Law]]>

$$ds^{2} = \frac{dr^{2}}{r^{2}} + r^{2}g_{\alpha\beta}dx^{\alpha}dx^{\beta}, \qquad \text{Poincare-AdS$_3$}$$

$$ds^{2} = \frac{dr^{2}}{r^{2}} + r^{2}\left(-dt^{2}+r^{2}d\phi^{2}\right), \qquad...

Correct coordinate transformation from Poincare-AdS##_3## to global AdS##_3##]]>

I'm trying to understand Einstein's field equations conceptually, does it describe space density in a region of space by any chance? Like there is more space in this region compared to this other region.

Thanks.]]>

I wanted to calculate the Ricci tensor for this metric for D=3. ([\eta_{\mu\nu} is the Minkowski metric in D dimensions)

I have found the following Christoffel...

Calculating Ricci Tensor]]>

In physics, I've always been told that gravity is a force that ALWAYS works between "objects" with mass. Now, it seems clear to me that if a feather and a hammer were to be dropped at the same time on earth (without air...

Why do objects fall at the same speed in free fall?]]>

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]]>

- A body frame rotates with a body. It need not be aligned to the rotation axis.
- Angular momentum vector always aligned with rotation axis (not deviates from it).
- An observer on the body surface (body frame) observes no motion on a body....

Rigid Body Rotation]]>

Absolute zero impossible]]>

the cyclic temperature profile leads to a time dependent density

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

Velocity in microchannel with temporal temperature variation]]>

Machine learning with particle physics]]>

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

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?]]>

It stated that according to the law of product of masses,...

Regular derivation on The Universal Law of Gravitation?]]>

I tried to answer the following questions is about the curve surface [itex]z= f (x, y) = x^2 + y^2 [/itex] in the xyz space.

And the three questions related to each other

A.)

Find the tangent plane equation at the point...

Finding volume surrounded by curve using polar coordinate]]>

*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]]>

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?]]>

Would...

chlorination in aerated water]]>

Flame in a background atmosphere of fuel]]>

If you live in a rural community with your own water system or your water supply comes in on plastic this sort of thing seems...

Losing neutral in the utility system]]>

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]]>

Where (on earth and/or in space) does this occur? And why don't ALL gamma rays...

Requirements for pair production]]>

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]]>

My wife just drew this

View attachment 93241]]>

View attachment 215517

I'm having some trouble with this problem as it seems my concept of the problem is completely wrong. Could someone look through my solutions and point out what I understood wrongly?

Thanks in...

Multiplicity/Probability. Einstein model of Solids]]>

I have to do one research of the transport of large nuclear reactors, and I need to have an idea of which is the DIAMETER, HEIGHT and WEIGHT of the reactor

I think that there are a lot of different dimension, but i want to know only approximately, because i don't have...

nuclear reactor size of a nuclear power plant]]>

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?]]>

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?]]>

“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?]]>

Would...

chlorination in aerated water]]>

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]]>

In the following problems let ##\alpha## be a cycle of length ##s##, and say

##\alpha = (a_1a_2 . . . a_s)##.

5) If ##s## is odd, ##\alpha## is the square of some cycle of length s. (Find it. Hint: Show ##\alpha =...

Proof about cycle with odd length]]>

I tried to use "Bonded contact" and...

Contact strength in ANSYS Workbench]]>

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In the books in the right side diagram they've reversed polarity of inductor to get equation:

V

But why?

I checked google and everywhere they had put inductor with positive...

Source free RL Circuit derivation]]>

View attachment 215443

I'm having some issues understanding a number of concepts in this section here. I attached the corresponding figure at the end of the post for reference.

Issue 1)

1st of all, I understand that a...

Writing Hamiltonian: Classical Mechanics]]>

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]]>

Chief Ray Angle and Field of View]]>

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]]>

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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?]]>

In the last picture , we can see that at time between 0 and infinity , the variation of pore pressure across depth is parabolic curve , why is it so ?

I think...

Variation of (pore pressure) due to consolidation]]>

Have $600.00 (not a cent more) to spend.

Anyone seen them go on sale other than Black Friday? If I wait around....anyone think I can nab one for $400.00?

He doesn't need a lot of storage. He just browses the web and gambles online at...

Do iPADs/iPAD Pros Ever Go on Big Sales?]]>

Not able to start new threads]]>

(1) You send a single photon through a half silvered mirror with a reflector at either side, as above, but instead of having two detectors, and a 50% chance of either going off, you just...

Beam splitter, one photon, one detector?]]>

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]]>

If you were to gain a few electrons and go running in Vancouver, what would be the magnitude and direction of the magnetic force that you would experience?

So I...

Determining Magnetic Field Direction]]>

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]]>

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]]>

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?]]>

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?]]>

Links: Nature...

First Interstellar Asteroid Found]]>

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

View attachment 215173

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]]>

Does black hole stop light or time?]]>

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

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]]>

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]]>

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