Well done to everyone who participated!

Your neighborhood/City

1. 0TheSwerve0

2....

PF Photo Contest Winners]]>

Im new here and dont know much about electronics so please bare with me as I try to explain what I would like to know.

If you have a classic design speaker it has a passive crossover inside consisting of mainly capacitors and inductors changing the frequency (or limiting) to send low...

Post sound amplification electronic crossover/devider]]>

In a penning trap where they use sideband detection of the particle, they need to "drive" it. But what does that mean? Is the position of the particle detected anywhere along this process?]]>

- Dry Air Gas Constant of
**286.9**from The Engineering Toolbox - Dry Air Gas Constant of
**287.22**from...

Why does the Dry Air Gas Constant vary?]]>

Its a great book and i really enjoyed it. However there is a claim in that seems a little odd to me.

In LQC singularities are resolved and replaced...

Carolo Rovelli on infinity in LQC]]>

Determine the following:

a) The average...

Motion Questions -- Acceleration of a race car...]]>

There are two charges with charge q and mass m]]>

pressure in the core of the earth]]>

eV = ½mv2

Where e is the charge of...

Thermal motion of an ionised gas molecule in an electric field]]>

This is just...

Falling Feather and ball in vacuum]]>

Light and the nature of space]]>

Satellite m=3 000kg, circular orbit at the height h = 300km above the Earth´s surface.

a/ calculate energy ( work ) for delivering satellites into orbit ?

b/ during 1 month the satellite approached the Earth of Δh=13,8 km....

Satellite in orbit]]>

Quantum-Mechanical treatment of circuits]]>

Interview with a Theoretical Physicist: Sabine Hossenfelder

...

Interview with a Theoretical Physicist: Sabine Hossenfelder - Comments]]>

Do particles of a rotating disk just change position or also spin?]]>

Style for references and bibliography]]>

They travel in opposite directions at this velocity for 2 hours...

Relativistic simultaneity and symmetry problem]]>

What could be wrong when the total inertia matrix of a robotic manipulator is non invertible when under certain values of the joint angles?

Thank you]]>

My wife just drew this

View attachment 93241]]>

First example: Imagine a book on the ground and I want to lift it.At first I apply a force just a little more than the gravitational force of the Earth so that it has some velocity. After the book gets that velocity, I keep my...

Question About Potential Energy]]>

Solve particle in a box problem using matrix mechanics?]]>

1) cause: ?

2) effect: motion]]>

Background of me:

compared to my engineering colleagues, my memorization, reporting skills (indeed i like oral or written presentation :) ) and...

mechanical or civil? (on me?)]]>

One mole of an ideal gas is reversibly compressed from 1 bar to P2

bar that results in temperature increase from 400 K to 950 K. Calculate the heat

transferred during the process and the final pressure, if the path followed by...

Polytropic Process]]>

Consider the ##xyzzy## algorithm below. This algorithm takes a linear collection (e.g., a list or array) of size ##n## as an argument (i.e., as the input to the algorithm) and produces no return value (i.e., has no output, but...

Algorithm Efficiency]]>

Show that for an arbitrary ideal holonomic system (n degrees of freedom)

[tex]

\frac{1}{2} \frac{\partial \ddot T}{\partial\ddot q_j} - \frac{3}{2} \frac{\partial T}{\partial q_j} = Q_j

[/tex]

where

Alternative Lagrange equation]]>

I have a homework problem which requires me to convert a word a user entered to Pig Latin by moving the first letter of the word to the end and adding an ay to it. For...

Simple C program involving arrays which cannot execute]]>

For what values of c is there a straight line that intersects the curve ##y = x^4+c x^3+12x^2-5x+2## in four distinct points ?

Concept of concavity, Vieta's formulas...

Values of c for which quartic curve intersects a line]]>

Actual value of normal reaction]]>

Let's say I have some sort of device that creates a lightning bolt, if I shot it at a watermelon in a vacuum or another target would it hit the target, or nothing happen because of the vacuum???]]>

But fun fun fun, lots of explosions and stuff.

People talking to their possible alternative selves and so on.]]>

How do you understand MWI?]]>

A uniform slender rod of length

Determine the distance...

Constrained Plane of Motion Problem]]>

Rotor Analysis -- Big deformation problem]]>

I've recently been reading a paper by Richard Muller and Shaun Maguire (which is not the exact topic of this post). In that work, the authors mention:

"We note that in quantum field theory, very small, localized and rapid events contain amplitudes that can be interpreted as taking...

QFT, event amplitudes and reversed time...]]>

How does one calculate fully quantum mechanical rate ($\kappa$) in the golden-rule approximation for two linear potential energy surfaces?

Attempt:

Miller (83) proposes...

flux-flux correlation function under Feynman's path integral]]>

View attachment 115061

The region is a circle with radius=a

View attachment 115062

Using Faraday's law to find E.

Dealing with the Left side of the second...

EMF find the electric field]]>

In this problem , it's a Internal Indeterminate truss .

So , I remove one of the redundant member , AC and solve the problem .

For the first part , I found the...

Internal Indeterminate truss]]>

So basically I have a train with two joined carriages which become separated (m1) Mass one =13563kg and (m2) Mass two =30394kg. the initial velocity of the joined carriages is 5.00m/s (u1).

When the carriages separate I have...

Two dimensional momentum problem]]>

Traveling through the Interstellar Medium]]>

##

\begin{bmatrix}

\sigma_{xx} & \sigma_{xy} \\

\sigma_{xy} & \sigma_{yy}

\end{bmatrix} = \mu...

Stress-strain; strain-displacement in 2-D; uniqueness]]>

Is there anybody who can help me with this question?

Example:

What is the enthalpy of CO2 in 200psig and 80deg.F?

I have a software, but I'd like to see the calculation steps.

Thanks

Ding]]>

instead of a circular shape?]]>

--Voyager I--]]>

My name is yrjosmiel. I'm a Physics and Math enthusiast. I decided to sign up to this forum because I think I will interact with people with the same interest and level of knowledge as I do. It's really difficult when nobody can understand what you're saying, isn't it?]]>

A homopolar generator consists of a metal disc of radius ##a## and a central axle which has radius ##a/4##. The disc has resistivity ##\rho## and thickness ##t##. It is rotated in a uniform magnetic field ##B## about an axis...

The slowing down of a farady disc]]>

I was imaging a race of quasi-crabs who entered the Empire of Man after having met only one human, an Oxford don type who gave them some ... interesting ... ideas of what the rest of the human race was like.]]>

Consider a 10 meter long gas column. We interrogate the gas molecules with a HeNe laser (lambda=633nm) at the minimum possible gas volume. If we focus the beam tightly, it will eventually diverge and the sampled gas volume will...

Laser Beam Diameter which Minimizes Volume?]]>

This week, the contest is all about the color GREEN. Your photo must have, as its main subject, something that is green in color.

Please note that since there is a wide range of shades of green, and that various screens may have varying...

PF Photo Contest - Green With Envy (3/25-3/31)]]>

I can't the use Fresnel equations as this is for total internal reflection.

If you don't know the answer to the above question, what about the same question, but for mirrors instead?

What are the...

Energy Loss During Total Internal Reflection]]>

Computing bending moment]]>

"Single-world interpretations... cannot be self-consistent"]]>

Show mathematically that a model with:

Ω_M0 = 3

Ω_Λ0 = 0.01

Ω_R0 = 0

Ω_T0 = 3.01

is a model that re-collapses in the future. Be certain to indicate at what value of the scale factor 'a' the expansion reverses and becomes...

Cosmology - determining if a model universe would recollapse]]>

I know that 2 EM wave with linear polarisations where one wave is shifted by π, they would...

Orthogonal Polarisation in EM waves and Interference]]>

With reference to the diagram attached.

i) What would be a suitable value for Rg and why

ii) If the drain current is 2mA, determine a suitable Q-point on the mutual characteristics and hence obtain a value for Rs

JFET Calculations]]>

Graduate degree program in Physics [from UG in India]]]>

I have been given the world's longest transistor problem as an assignment Here is the circuit:

View attachment 115001

I am asked to find:

a) V1, V2 and V3 using DC analysis

b) AC equivalent circuit

c) AC tension...

BJT and MOSFET complete analysis]]>

A cylindrical wire of thermal conductivity k, radius a and resistivity p uniformly

carries a current I. The temperature of its surface is fixed at T0 using water cooling.

Show that the temperature T(r) inside the wire at...

Thermal Diffusion with Heat Source]]>

Keep It Simple, Stupid]]>

∑Fx = 0

I found F

Show that the 3 wave functions are normalized

The above image is...

Show that the wave function is normalized]]>

What is the most correct way to write a vector in GR?]]>

We are a research group doing research in computational sciences. We are considering ordering new computers for our research. I was wondering if anyone could advise us regarding the hardware specifications needed to run heavy and time-expensive programs, specifically in...

Inquiring about Computer HW Specifications for Time-Intensive Calculations]]>

I have a question to all of you. This question is based on the example which is located here: http://galileo.phys.virginia.edu/classes/252/time_dil.html

I understand it but there is one thing is still unclear to me. So, here it is:

Again we have

time dilation: a working example. Help me to understand a little thing :)]]>

Control theory]]>

Thanks.]]>

What is the effect of the load cycle frequency on the SN curve (Wöhler curve)? Especially when the frequency matches the natural frequency of the component/material?

Instinctively, I would think that at the natural frequency the number of load cycles until fracture is lower than at any...

SN diagram vs. Cycle Frequency]]>

The path that the rays make is different as is is if the...

why can you solve system of lenses combining the effects?]]>

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]]>

Could a powerful enough laser burn through sand or ash and work effectively?]]>

$$\int_{-\infty}^\infty f(x) \sqrt{\delta(x-a)} dx$$

How is this integral evaluated?]]>

I was just wondering when is a right handed neutrino a heavy neutral lepton?

I know that RH neutrinos show up in a number of extension to the standard model, for example the neutrino minimal standard model (vMSM) and Left-right symmetric extensions.

Ive heard them being referred to as...

When is a right handed neutrino a heavy neutral lepton(HNL)?]]>

I want to find out real locations of videos which are played by Adobe Flash Player. Through reading many articles I realize the only feasible way is to sniff the HTTP traffic and even this method can fail. Is this thought correct?

Senmeis]]>

Please start off with "Today I learned". Keep commentary to a minimum and just LIKE posts. I'll start!

Today I learned that you clean...

Today I learned]]>

What's the projection of the resultant force onto an said axis?

Sine Law, Cosine Law

For problem 2/20, the projection onto the b axis was found by multiplying...

Statics Question: Projection]]>

I am trying to modeling financial markets.

Looking for google, I have found this global variable:

long idum

In the main(), it is defined as

idum = -9132434

or in many other ways.

I am using the following libraries:

#include <stdio.h>

#include <stdlib.h>

#include <math.h>...

Long idum in Modeling Financial Market]]>

Canal rays, i.e., positive ion rays are generated in a gas discharge tube. How often does an ion (r= 0.05 nm) collide with an atom of the ideal ﬁller gas(r= 0.1 nm) if it travels 1 m in a straight path through the discharge tube...

approximating number of collisions in canal ray tube]]>

My geometry is a prototype of a hydroelectric plant. It consists of a tank, penstock, a gate and a test section; my aim is to simulate turbulent flows on this prototype. My geometry consists of two zones, a zone filled with water (red color) and a zone filled with air (blue color). The...

How I can determine the free surface level ?]]>

https://news.utexas.edu/2017/02/28/goodenough-introduces-new-battery-technology

Lithium-Ion Battery Inventor Introduces New Technology for Fast-Charging, Noncombustible Batteries...

New battery technlogy (John Goodenough)]]>

Sadly, Wiki is a stub, and most of the relevant literature is pay-walled.

As I understand it, deep vents may generate a lot of pumice, but it never reaches the surface, just stays on the vent's flanks....

Submarine volcanic vents and pumice rafts...]]>

(a)

A spaceship at rest in a certain reference frame S is given a speed increment of 0.50c. Relative to its new frame, it is then given a further 0.50c increment.This process is continued until its speed with respect to its...

Special relativity and particle accelerator]]>

Estimate the total harmonic distortion [THD] present in the current waveform using the formula:

##THD\left(I\right)=\frac{1}{I1}\sqrt{\sum_{n=2}^\max\left(In\right)^2}\times 100\%##

Harmonic Distortion in a current waveform]]>

If I choose point 1 ...20kg x 1m = 20kg x 3m.......seesaw right side will fall down

If I choose point 2....20kg x 2m = 20kg x 2m.......seesaw stay horizontal

So this...

Choose point for calculate moment?]]>