"Our discussion of measurement will be...

General quantum measurements]]>

My name is Abbey and I am currently taking Physics II and Thermodynamics college classes for my Bachelor's in Electronics Technology and this site is an amazing find! Usually I have issues starting problems but once I figure out how to start it, I'm good. Thank you to this great...

Hi, I'm Abbey]]>

How about the notion that regarding our universe, it didn't expand from an inert pinpoint but is instead a breach in the "wall" of an even larger system - i.e. essentially like a volcanic eruption. Of...

Could it have been the Big Leak and not the Big Bang?]]>

Hello all,

I've worked through the problem below, but I feel my answer is incorrect. I would appreciate it if someone could check my work.

Water is pumped from a lower reservoir to a higher reservoir by a pump that...

Thermodynamics- determining mechanical power]]>

Here is the last page of part 5.

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

At noon two boats P and Q have a position vector (i+7j)km and (3i+8j)km respectively to the origin O.

i and j are unit vectors in direction to East and north respectively

P is moving south east at 5√2 km/h and Q is moving at a...

I need help with this question about vectors]]>

https://www.economist.com/news/scie...ry-fundamental-physics-frustrating-physicists

It states that after concluding that there has been any evidence...

The ever-increasing proton lifetime]]>

A removable plate is mounted in the end of a swimming pool. The plate is 60cm square with the top edge 30cm below surface of water. Compute the force on plate and distance to centre of pressure below surface of water.

2. Relevant equations....

Center of pressure calculation]]>

where ##i=1,2,3##

But what about vectors in Minkowski space? Is it true that

$$P: y_{\mu} \rightarrow -y_{\mu}$$

where ##\mu=0,1,2,3##.

If yes how...

vectors in Minkowski space and parity]]>

I revised a resume for data science positions. I empathized on skills that are needed for the positions like statistics/mathematics and programming. I mention that I am familiar with the theory of many machine learning algorithms and Python libraries used for data analysis. I still...

Writing a resume for data science positions]]>

]]>

I guess my question is will I have to start from the bottom of the pay scale when I graduate? By the time Im...

Tech getting Eng. degree. Will my work exp. transfer?]]>

I have a few questions about this.

If this is correct why are we taught to use...

Newton’s Laws and Euler’s laws]]>

How do I control this heater?]]>

The equation

a. *y = -A sin(kx - wt + pi/2)*

b.*y = A cos(kx - wt)*

c.*y = -A cos(kx - wt)*

d.*y = -A sin(kx - wt - pi/2)*

e.* **y = A sin(kx - wt...*

b.

c.

d.

e.

Oscillatory motion equation in sine function]]>

In Dudas Pattern Classification, he Writes that [itex] P(x,\theta|D) [/itex] can always be written as [itex] P(x|\theta,D)P(\theta|D) [/itex]. However, I cannot find any justification for this. So, why are these Equal?]]>

There is a charged particle at height h over a circular area of radii R, then I have to calculate the capacitance. This is useful when somebody want to calculate energy harvesting, antennas, sensors that measures ions in plasma...

What would be the capacitance of a particle on a plate?]]>

A different SMPS idea]]>

- Tensors of odd rank (e.g. vectors) reverse sign...

pseudotensors in different dimensions]]>

Experiments probing macroscopic limits of QM]]>

This article gives a maximum weight of 2.16 solar masses, and an infinitesimal addition would turn it into a Black hole. I can not find a paper to support this article so do you think it is correct?]]>

Thanks.

--

lightarrow]]>

If we assume a massless quantum object then we have the relationship ##\Delta E = c\Delta p## so that the above uncertainty relationship becomes

$$\Delta E \ge \frac{\hbar c}{\Delta x}.\tag{1}$$

I understand that if we have...

Are the energy fluctuations in space real or virtual?]]>

I have a question: some syntax in programming are easy to remember, but others are not. Usually, when I am stuck at how to implement an idea, or don't remember the exact syntax of something I need to use, say in Python, I search it on the Internet, and I almost always find an answer....

Memorizing syntax/steps vs. looking things up]]>

How to find the domain of functions of an operator]]>

1. AlexCaledin

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2. lekh2003

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3. Orodruin

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4. Rubidium_71...

VOTE PF Photo Contest - Water, Water, Everywhere!]]>

How to make a short range, remote-controlled electromagnet?]]>

Hi All,

I submitted some homework in for marking & received back that on my last question (iii) I had worked out 37.5 wrong, could someone please have a look at...

A vehicle of mass 1200 kg accelerates]]>

Cheers]]>

Hello Everyone, a pleasant good morning to all :)

I will attach an image that shows a diagram of a circuit.

The question based on this picture is as follows:

''When switch S is closed, the Lamp L, lights. Explain how this...

Explain How Lamp in Circuit A Light When Switch S is closed]]>

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internal change = $$\frac{3}{2}n.R.(T2 - T1)$$

Work = P.ΔV

1) T2 = $$\frac {P2. V2 . T1 }{P1 . V1} = 1.2 * 10^3$$

2) Q = Internal...

Find the work done on a monoatomic gas in this P-V diagram]]>

BS Mechanical Engineering

MS Mechanical Engineering (in progress)

Hello PF]]>

Or with none of them, only pure thought?]]>

There's been a flurry of research being done in Japan on a banned topic related to "LENR". I was wondering what is the burden of proof required to change minds on this topic? How or where may it be presented? Is the guiding principle that if it cannot be described by...

Are banned topics subject to revision?]]>

So I would like to ask, how does one use the AOPS books, are they meant to be supplementary to a full textbook? Or are they used for introducing new concepts that you would have leant in a textbook etc.

I am hoping to use the AOPS...

How to use AOPS books?]]>

I'm currently doing the project and need to estimate the force that will act on the micron size superparamagnetic particle in the field of permanent magnet.

I found several article there similar problem is solved, but I a bit confused. I hope someone could hep me.

So, the main equation...

Force acting on superparamagnetic particle]]>

Splitting force vectors into components]]>

Would aliens need our resources?]]>

I'm reading about the solution of the wave equation in free space on Stratton - Electromagnetic Theory and Snider - PDE and I got a little confused. The wave equation in 3D (plus time) is the following $$\frac{\partial^{2} \Psi (x,y,z,t)} {\partial t^{2}}=\nabla ^{2}\Psi...

Wave equation in free space]]>

The Hypatia Stone is a small meteorite from SW Egypt. Petrographic and chemical analysis by a group of researchers mostly from University of Johannesburg found element abundances and other unique chemical anomalies in the...

Meteorite older than Earth]]>

How things Float]]>

if ## f(x)= \int_x^3 \sqrt {1+t^{16}} dt ## find f'(x)

let ## x = 1+t^{16},## → ##\frac {dx}{dt},= 16t^{15},##

## y= x^{1/2} ## →##\frac {dy} {dx},=...

integration question]]>

14.34 The 0.5-kg bob of the pendulum travels a complete circle about the pivot

point O. Determine the smallest possible speed of the bob in position A if it is

suspended from (a) a rigid rod of negligible mass; and (b) a string...

Determine the smallest possible speed of the bob at A]]>

2. "The moons of Jupiter and Saturn"

3. "Design a solar system mission"

We are now moving on beyond the solar system. Stars, galaxies, and...

Astronomy Project]]>

Mentor Change Jan 2018]]>

Finish the ME program (BS) or switch to a BA in mathematics?]]>

I have some pharmacokinetic data for a molecule that was administered in rat, first IV (intra-venously), then PO...

Fitting two models in sequence with parameters in common]]>

For each of the following cases, represent on the trajectory, the velocity and tangential and normal components of the acceleration at times t1 and t2 of a mobile that moves according to the graph of s (arc) versus t (time) on...

Kinematics problem]]>

From the phase diagram what can be said of the porosity, mechanical strength, and density of various materials in the diagram?

View attachment 218399

Interpreting Ternary Phase Diagram]]>

Investigate parity of this term:

$$P(G_{\mu \nu}^a)=+G_{\mu \nu}^a$$

$$P( \tilde{G}^{a, \mu \nu} ) =-G_{\mu \nu}^a$$

It is obvious. But what about...

Parity of theta term of Lagrangian]]>

If Dark Matter and Dark Energy exist, what produces it?]]>

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##V=V^u \partial_u ##

I am a bit confused with the notation used for the Lie Derivative of a vector field written as the commutator expression:

Not using the...

Lie derivative vector fields, show Leibniz rule holds]]>

A First Idea of Quantum Field Theory - 20 Part Series

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...

A First Idea of Quantum Field Theory - 20 Part Series - Comments]]>

Apologies if this is the wrong place to ask, but I was wondering how much data there was in a language (let's say English).

So for example, if you were to program a computer to speak English fluently, how much data would all the vocabulary and rules of syntax take up?

Thanks]]>

Mathematical Quantum Field Theory - Gauge symmetries

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...

Mathematical Quantum Field Theory - Gauge symmetries - Comments]]>

I've done a bit of research and found this two posts:

https://www.physicsforums.com/threads/showing-deadly-acceleration.909104/#post-5726115...

Simulating Jules Verne Earth to the Moon trip?]]>

Irrational inequalities √f(x)>g(x) and √f(x)>g(x)]]>

Hi,

I have done part a) by using the expression given for the lie derivative of a vector field and noting that if ##w## is a vector field then so is ##wf## and that was fine.

In order to do part...

Component of Lie Derivative expression vector field]]>

What courses of the following are the best for my field?]]>

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The emf gets induced due to the changing flux.

The flux through the rod remains 0. So, there is no induced emf.

I don’t know...

Induced electric field]]>

Dealing with stress in college, my situation.]]>

a lot of my fellow music friends either listen to classical music, or really emo stuff

admittedly I listen to classical music quite often myself, and though I'm...

Should musicians be shamed for liking pop music?]]>

https://www.quantamagazine.org/what-makes-the-hardest-equations-in-physics-so-difficult-20180116/]]>

von Neumann Entropy of a joint state]]>

Power Production at Hanford N-Reactor]]>

teacher needs maths assistance please]]>

I would like to ask you what happens when you change (gradually) a mass of one body in a classical two-body-problem.

May it lead to such results?

View attachment 218611

Many thanks.

Flor]]>

Software - Suspension Analyzer by Performance Trends

In order to understand the complexity of a Formula Cars suspension, a basic knowledge of the stock car suspension should first be mastered. When...

Race car suspension Class]]>

I'm trying to adapt the Bragg condition for the David-Germer experiment, so I can then use their experimental results to show that the measured wavelength is compatible to the wavelength theorised by De Broglie. However I'm having issue with the calculation, any help would be much...

Davison-Germer experiment - Bragg condition]]>

The total force acting down is 30N, so therefore the...

Forces: hand holding a tray]]>

Maybe correlation doesn't imply...

UV light + electric current = boom?]]>

A cylinder of radius

a) Calculate the electric field strength a distance

Calculating electric field strength]]>

But for any inference that is going to deal with ideas of causality, it's primarily a subject matter concern, which relies on mostly on judgment calls and intuition....

Limits of Machine Learning?]]>

Academic/Career Crossroads]]>

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First derivative=maxima/minima/vertical tangent/rising/falling

When f'(x)>0 ? the function rises

Deriving relative to x:...

Graph drawing—Finding the points on a curve that are nearest to the origin]]>

The situation I am stuck with involves a system of 4 PDEs describing plasma in a cylinder. The dependent variables being used are Vr, Vt, Vz, ni, and the independent variables are Rr,...

Boundary Conditions for System of PDEs]]>

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In the region |z|<1 ,

E(z) = -dV/dz = 10z

This means there is a variable electric field in the region -1<z<1 .In the +z...

Potential and charge density]]>

https://www.wired.com/story/when-spock-met-plato/

In the end it was a disappointing meeting with expectations of Spock not met by either side.]]>

pi(x) from zeta]]>

Coupling constants with fractional dimensions]]>

...

Decarbonizing an Engine with Water: Myth or Fact?]]>

Obviously we are talking about in the context of FTL travel, probably one of the most asked about topics there is. Everyone wants it to be a thing. While I see the benefits of it, I don't care about if it could be possible or not....

Why Is a Violation of Causality a Problem?]]>

Half way through journey inside the tunnel, your ship suddenly makes a sharp right turn and penetrates the wall of the tunnel and leaves the wormhole -failing to complete the full journey to point B

Where...

Exiting wormhole prematurely]]>

Asymmetrically charged capacitor]]>

A child pushes a block of wood with a mass of 0.72 kg across a smooth table. The block starts from a position of rest and after 2 seconds its has a velocity of 1.6 m/s [forward]

The coefficient of friction is 0.64.

a) Find the...

Applications of Newton's laws (friction related)]]>

The textbooks that the...

*BEST* Calculus 3 Textbook for self study]]>

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Heya, Chaos checking in]]>

Derive the relativistic Euler equation by contracting the conservation law $$\partial _\mu {T^{\mu \nu}} =0$$ with the projection tensor $${P^{\sigma}}_\nu = {\delta^{\sigma}}_\nu + U^{\sigma} U_{\nu}$$ for a perfect fluid....

Orthogonal Projection of Perfect Fluid Energy Momentum]]>