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no tidal bulge

Beyond the Tidal Bulge

Overview That there is no tidal bulge is the key premise of this article. Upper-level oceanography undergraduates and above know this. Yet the tidal bulge is still used to portray why the Moon is receding the Earth. If there is no tidal bulge, some other explanation is in order. That other explanation uses gravitation as…

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Physics Olympiad Corrections

Corrections to the Australian Physics Olympiad Questions and Solutions

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ref: asi.edu.au/programs/past-exams/physics-olympiad-past-exams/ Classification of issues: [1*] Quibble regarding the solution. [2*] Clearer problem…
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A Principle Explanation of the “Mysteries” of Modern Physics

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All undergraduate physics majors are shown how the counterintuitive aspects ("mysteries") of time dilation and length contraction in special relativity…
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Exploring the Anatomy of Compton Scattering

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Introduction In this article, we take as our starting point the original equations which Compton drew up and solved in his ground-breaking 1925 article:  From…
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Learning the Twin Paradox for Freely-falling Observers

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The "twin paradox" is often discussed in the introductory treatment of special relativity. Under "twin paradox" we understand the fact that if two twins…
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Create an Android Ringtone Picker with Ringtonemanager Class

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In this article, I will show you how to create a ringtone picker using the RingtoneManager class in Android. You will be able to get the list of tones,…
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AI and Learning: How It Impact Our Future

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We asked our PF Advisors “How do you see the rise in AI affecting STEM in the lab, classroom, industry, and or in everyday society?”. We got so many…
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How AI Is Changing STEM

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We asked our PF Advisors “How do you see the rise in A.I. affecting STEM in the lab, classroom, industry and or in everyday society?”. We got so many…
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We asked our PF Advisors "How do you see the rise in AI affecting STEM in the lab, classroom, industry, and or in everyday society?". We got so many great…
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Today we get to know a little more about Engineering Mentor jrmichler! Tell us a bit about your education and academic years Two years college (UW-Madison)…
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Are Electromagnetic Waves Always Transverse?

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In this insight, we shall endeavor in the realm of classical electrodynamics and examine whether EM waves are always transverse. We shall make use of Jefimenko's…
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How to Solve Second-Order Partial Derivatives

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Introduction A frequent concern among students is how to carry out higher order partial derivatives where a change of variables and the chain rule are…
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Is Pressure A Source Of Gravity?

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In a previous series of articles, I posed the question "Does Gravity Gravitate?" and explained how, depending on how you interpreted the terms "gravity"…
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Massive Meets Massless: Compton Scattering Revisited

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Introduction In a previous article entitled "Alternate Approach to 2D Collisions" we analyzed collisions between a moving and stationary object by defining…
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In a previous article, I discussed why scientists (among others) are rarely interested in considering a new theory proposed by a non-scientist: because…
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The Analytic Continuation of the Lerch and the Zeta Functions

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Introduction In this brief Insight article the analytic continuations of the Lerch Transcendent and Riemann Zeta Functions are achieved via the Euler's…
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Dark Energy Part 3: Fitting the SCP Union 2.1 Supernova Data

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In Part 1 of this 3-part series, I explained kinematics in Einstien-deSitter (EdS) cosmology and in Part 2, I explained kinematics in ##\Lambda##CDM cosmology…
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Dark Energy Part 2: LCDM Cosmology

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This is Part 2 of a 3-part series explaining evidence for so-called “dark energy” leading to a current positive cosmological acceleration. The evidence…
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A Beginner Physics Guide to Baryon Particles

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Baryon Introduction At the beginning of the 20th century, it was thought that all matter consisted of only three particles: the electron, the neutron,…
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Slowly Lowering an Object in a Static, Spherically Symmetric Spacetime

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In the first two articles in this series, we looked at the Einstein Field Equation and Maxwell's Equations in a static, spherically symmetric spacetime.…
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The Reappearance of Supernova (SN) Refsdal

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Supernova (SN) Refsdal Key Points Astronomers have been trying to understand space for thousands of years. Supernova Refsdal was the first known…
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Dark Energy Part 1: Einstein-deSitter Cosmology

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In this 3-part series, I want to motivate the (re)introduction of the cosmological constant ##\Lambda## into Einstein's equations of general relativity…
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Is there Evidence for the Big Bang?

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Big Bang Key PointsHubble's law (redshift of galaxies) and the Doppler effect provide direct evidence for the universe expanding away from our reference…
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The Evolution of the Universe, Cosmic Web and Connections

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The universe was not perfectly uniform when it started, some areas had a higher density than others. During the evolution of the universe, these areas…
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Gaia and the Race to Detect More Gravitational Waves

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Gravitational waves (GW’s) are disturbances in spacetime produced by any massive object moving asymmetrically. However, only the most massive and most…
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3 Possible Models For Why Uranus Spins on Its Side

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Uranus spins on its side. Uranus has an obliquity (tilt) of 98º, making its axis of rotation closer to the ecliptic plane than any other planet. It is…
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Black Holes Are Not Empty Voids

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Black Hole Key PointsBlack Holes (BH’s) have a gravitational pull so strong that nothing, not even light, can escape it BH’s can be divided…
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A Path to Fractional Integral Representations of Some Special Functions

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Introduction This bit is what new thing you can learn reading this:) As for original content, I only have hope that the method of using the sets $$C_N^n:…
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Note: It is assumed that the reader has read part I of the series. Introduction The ambiguity and flaws discussed in part I can be resolved using the…
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An Alternate Approach to Solving 2-Dimensional Elastic Collisions

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Introduction This article follows on from the previous on an alternate approach to solving collision problems. In that article, we determined the equal…
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Is Mechanical Energy Conservation Free of Ambiguity?

Introduction "Close to any question that is in the textbook, there is another question that has never been answered that is interesting." [Stephen Wolfram,…

How to Recognize Split Electric Fields

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Introduction In a previous Insight, A New Interpretation of Dr. Walter Lewin’s Paradox, I introduced the fact that there are two kinds of E fields. …
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An Introduction to the Generation of Mass from Energy

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Introduction This article is essentially an addition to the previous one on (mainly) inelastic collisions to include the particular case of inelastic…
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An Alternative Approach to Solving Collision Problems

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Introduction Collisions are very much a stock item in any school physics curriculum and students are generally taught about the use of the principles…
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Mathematician Mary Somerville Features in Google Doodle

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The Google Doodle for 2 February 2020 celebrated Mary Somerville, the Scottish polymath and science writer, and Caroline Herschel, the joint first-ever…
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Why We Don’t Discuss Perpetual Motion Machines (PMM)

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Authorship Contributions From AnorlundaYou may want to believe the article you read, or the video you saw, or you may be very proud of your PMM invention.…
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Guide to C++ Programming For Beginners

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Contents 1. Getting a C++ Compiler and Compiling Your First Program 2. Simple Datatypes and Declarations 3. Operators and Expressions 4. Input and…
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Accurate Fluid Dynamics By Video Analysis

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IntroductionProviding accurate fluid dynamics experiments for undergraduate laboratories is challenging in several ways, including reproducibility,…
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Tell One Wood from Another: Basic Wood Anatomy

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As a long-time woodworker, I have an interest in being able to tell one wood from another, and in the process of learning how to do that, I've developed…
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Explore the Fascinating Sums of Odd Powers of 1/n

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The goal is to get a little bit closer to the values of the zeta function (ζ(s)) and the eta function (η(s)) for some odd values of s. This insight is…
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Introduction In this article, we will discuss the fundamentals of the diffraction grating spectrometer.  The operation of the instrument is based upon…
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Intro to the Ionization Energy of Atomic Hydrogen

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Introduction In previous articles relating to various transition energies in Hydrogen, Helium, and Deuterium we have employed the following formula for…
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Time to test your science knowledge with a fun 10 question quiz with random questions across all sciences. Difficulty is easy to medium. As always, post…
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SOHCAHTOA: Seemingly Simple, Conceivably Complex

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What is SOHCAHTOA SOHCAHTOA is a mnemonic acronym used in trigonometry to remember the relationships between the sides and angles of right triangles.…
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An Intro to the Systemless Interface of Rooting Android Phones

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What you can learn from this article:What is meant by rooting an Android phone Steps to take before proceeding to root your phone Google’s…
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Answering Mermin’s Challenge with the Relativity Principle

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Note: This Insight was previously titled, "Answering Mermin's Challenge with Wilczek's Challenge." While that version of this Insight did not involve any…
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Exploring Bell States and Conservation of Spin Angular Momentum

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In a recent thread, I outlined how to compute the correlation function for the Bell basis states\begin{equation}\begin{split}|\psi_-\rangle &=…
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Modern Physics Understood as an Unrecognized Kuhnian Revolution

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People often claim on Physics Forums and in the foundations community proper that quantum mechanics is "incomplete." Indeed, Lee Smolin recently wrote…
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Relativistic Treatment of the DC Conducting Straight Wire

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Introduction The direct-current-conducting infinitely long wire is often discussed in the context of relativistic electrodynamics. It is of course a completely…
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Revisiting The Deuterium Lyman Alpha Line Experiment

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Introduction In this article, we will be revisiting a somewhat understudied (and seemingly unrepeated) experiment to measure the Deuterium Lyman Alpha…
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Signature of the Sun: Analyzing the Solar Balmer Series Lines

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Introduction We are in many ways a fortunate generation having so many wonderful tools at our disposal on account of the "silicon revolution". The advent…
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Clearing Misconceptions and Some Tips on Debloating Android Phones

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What is bloatware? When you unbox your new phone, it comes with Android which is pre-installed by the manufacturer. This is termed “stock firmware”.…
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Recursion in Programming and When to Use or Not to Use It

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Recursion is quite simple. It's a subroutine calling itself. It's surprising but some problems that look quite hard can be trivial using recursion - but…
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Understanding Bohr’s Helium Lines

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Introduction In a previous article "Calculating the Balmer Alpha Line" we mentioned how accurate predictions of the spectral lines of singly ionized Helium…
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Maxwell’s Equations in Magnetostatics and Solving with the Curl Operator

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Introduction: Maxwell's equation in differential form ## \nabla \times \vec{B}=\mu_o \vec{J}_{total}+\mu_o \epsilon_o \dot{\vec{E}}  ##  with ## \dot{\vec{E}}=0…
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What Are the Thermodynamics of Black Holes? A 5 Minute Introduction

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Definition/Summary The four laws of black hole thermodynamics are as follows...The Zeroth Law Surface gravity [itex](\kappa)[/itex] is constant…
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What is Impedance? A 5 Minute Introduction

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Definition/Summary The impedance of a load (a combination of components) in an AC current is a complex number [itex]Z\ =\ R+jX[/itex] where [itex]R[/itex]…
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How to Avoid Breaking Physics With Your “What If” Question

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We get a lot of "what if" questions here on Physics Forums. This article will explore three different types and then some suggestions for students who…
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Learn the Basics of Dimensional Analysis

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As a university teacher and as a PF member, I have often noted that students are largely unaware of or not using dimensional analysis to help them in their…
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What is Mass Inflation? A 5 Minute Introduction

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Definition/Summary Abstract from Poisson and Israel's 1990 paper, 'Internal structure of black holes'-'The gravitational effects associated with the…
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How to Zip Through a Rotating Tunnel Without Bumping Into the Walls

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Preface While browsing through unanswered posts in the Classical Physics Workshop, I came across a gem at the link shown below.  For the reader's convenience,…
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Calculating the Balmer Alpha Line: Atomic Hydrogen

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Introduction Most readers acquainted with the hydrogen spectrum will be familiar with the set of lines in the visible spectrum representing transitions…
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Maxwell’s Equations in a Static, Spherically Symmetric Spacetime

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In the first article in this series, we looked at the Einstein Field Equations in a static, spherically symmetric spacetime. In this article, we are going…
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What is Potential Energy? A 5 Minute Introduction

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Definition/Summary Potential energy is simply another name for (minus) the work done by a conservative force.Since the work-energy theorem states…
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How to Find Potential Functions? A 10 Minute Introduction

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Definition/Summary Given a vector field ##\vec F(x,y,z)## that has a potential function, how do you find it? Equations $$\nabla \phi(x,y,z) = \vec F(x,y,z)$$…
Moment of Inertia

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Definition/Summary The moment of Inertia is a property of rigid bodies.It relates rotational force (torque) to rotational acceleration in the same…
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Understanding Superposition Physically and Mathematically

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What is superposition Superposition is a fundamental concept in physics and mathematics, particularly in the fields of wave theory and quantum mechanics.…
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What Thermodynamics and Entropy Means

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Introduction The student of thermodynamics, as they consider pistons and ideal gasses and such, often begin to grasp the nature of entropy only to find…
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What is a Linear Equation? A 5 Minute Introduction

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Definition/Summary A first-order polynomial equation in one variable, its general form is [itex]Mx+B=0[/itex] where x is the variable. The quantities…
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The Einstein Field Equation in a Static, Spherically Symmetric Spacetime

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This will be the first of several articles which will provide, for reference, useful equations for static, spherically symmetric spacetimes. This is a…
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Proofs in mathematics are what mathematics is all about. They are subject to entire books, created entire theories like Fermat's last theorem, are hard…
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How to Evaluate a Camera Lens for Performance

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Quantum Mechanical Commutator

The Classical Limit of Quantum Mechanical Commutator

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The Classical Limit of Commutator (without fancy mathematics) Quantum mechanics occupies a very unusual place among physical theories: It contains classical…
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Understanding Precession in Special and General Relativity

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The Absolute Derivative In relativity we typically deal with two types of quantities: fields, which are defined everywhere, and particle properties, which…
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What is a Fibre Bundle? A 5 Minute Introduction

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Definition/Summary Intuitively speaking, a fibre bundle is space E which 'locally looks like' a product space B×F, but globally may have a different…
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What is a Real Number? A 5 Minute Introduction

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Definition of real numbers Real numbers are a comprehensive set of numbers that encompasses all possible values on the number line. They include both…
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Equations of State for Photon Gas and Relativistic Electron Gas

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This Insight develops equations of state that are useful in calculations about cosmology and about the insides of stars. The first calculation is for a…
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What is the Double Slit? A 5 Minute Introduction

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Definition/Summary The double-slit is a simple configuration used to demonstrate interference effects in waves.Equations At distances that are…
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What is Integration By Parts? A 5 Minute Introduction

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The 7 Basic Rules of Quantum Mechanics

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For reference purposes and to help focus discussions on Physics Forums in interpretation questions on the real issues, there is a need for fixing the common…
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Clarifying Common Issues with Indistinguishable Particles

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A Formal Definition of Large-Scale Isotropy

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What is a Parabola? A 5 Minute Introduction

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What is a Parabola? A parabola is a U-shaped curve in mathematics that is defined by a specific set of points. It is a fundamental geometric shape that…
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When Renewable Energy Meets Power Grid Operations

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The electric power industry faces much turmoil in the coming decades.  The business model of the electric utility company (public or private) may not…
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What Is a Limit of a Function? A 5 Minute Introduction

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What is a limit? In mathematics, a limit is a fundamental concept used to describe the behavior of a function or sequence as it approaches a particular…
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Demystifying Parameterization and Surface Integrals

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What is Lie algebra? A 5 Minute Introduction

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Definition/Summary A Lie algebra ("Lee") is a set of generators of a Lie group. It is a basis of the tangent space around a Lie group's identity element,…
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What Discovery Will Be the Revolutionary Within 20 Years?

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We asked our Physics Forums Science advisors "What technology or scientific discovery will be the most revolutionary within the next 20 years?" Here are…
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Here is another version of proof of Maupertuis's principle. This version is pure Hamiltonian and independent of the Lagrangian approach.The proof…
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Exploring Fermi-Walker Transport in Kerr Spacetime

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In the last two posts in this series, we developed some tools for looking at Fermi-Walker transport in Minkowski spacetime and then applied them in Schwarzschild…
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How to Create a Universe: Instructions for an Apprentice God

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(-: ##~~~## A fantasy to be read at leisure time ##~~~## :-) Written October 7, 1999 to relax from the strains of working on a new interpretation of quantum…
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What is a Tangent Line? A 5 Minute Introduction

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Definition/Summary The tangent to a curve in a plane at a particular point has the same Gradient as the curve has at that point.More generally, the…
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A Classical View of the Qubit

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This Insight article is part of my paper Foundations of quantum physics III. Measurement, featuring the thermal interpretation of quantum physics. See…
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Learning Fermi-Walker Transport in Schwarzschild Spacetime

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In the first post in this series, we introduced the concepts of frame field, Fermi-Walker transport, and the "Fermi derivative" of a frame field, and developed…
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Aiming High and Managing Distractions as Keys to Success for Science Majors

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Over the years, I've noticed some distinct trends among the physics and chemistry majors I've mentored and worked with.Those with GPAs in the 3.8-4.0…
AVX-512 Programming subtotals

AVX-512 Programming: Extracting Column Subtotals from a Table

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In this Insights article I'll present an example that shows how Intel® AVX-512 instructions can be used to read a whole row of data in a single operation,…
Minkowski Spacetime

Fermi-Walker Transport in Minkowski Spacetime

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This is the first of several posts that will develop some mathematical machinery for studying Fermi-Walker transport. In this first post, we focus on Minkowski…
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Definition/Summary Virtual particles are a mathematical device used in perturbation expansions of the S-operator (transition matrix) of interaction in…
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The Sum of Geometric Series from Probability Theory

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Here I present a simple (but to the best of my knowledge, new) derivation of the formula for the sum of the infinite geometric series. The derivation is…