# Expert Math and Science Articles

## An Alternative Approach to Solving Collision Problems

Introduction Collisions are very much a stock item in any school physics curriculum and students are generally taught about the use of the principles of conservation of momentum and energy for solving simple collision problems in one dimension. In this article we will be examining a very common type of collision problem: the inelastic or…

## Recent Entries

### 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.…

### 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,…

### Want to Tell One Wood from Another? Learn 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…

### 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…

### Fundamentals of the Diffraction Grating Spectrometer

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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…

### 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…

### Grab Bag Science Quiz

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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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### What is the Moment of Inertia? A 10 Minute Introduction

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Definition/Summary Moment of Inertia is a property of rigid bodies.It relates rotational force (torque) to rotational acceleration in the same way…

### Understanding Superposition

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IntroductionOne should first and foremost understand that superposition has both a mathematical an a physical meaning, or rather it originates as…

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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 $Mx+B=0$ where x is the variable. The quantities…

### 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 symmeetric spacetimes. This is a…

### What are Significant Figures? A 5 Minute Introduction

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Definition/Summary Significant figures (commonly called "sig figs") are the number of figures (digits) included when rounding-off a number.For example,…

### How Most Proofs Are Structured and How to Write Them

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... or the answer to: "I have no idea where to start!" Proofs in mathematics are what mathematics is all about. They are subject to entire books, created…

### Lens Performance Testing: Evaluating a Camera Lens

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I've done plenty of imaging performance testing on a variety of systems, from millimeter wave through UV. Until very recently, such testing required expensive…

### 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…

### 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…

### 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…

### What is a Real Number? A 5 Minute Introduction

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Definition/Summary The real numbers are most commonly encountered number system, familiar to the layman via the number line, and as the number system…

### 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…

### 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…

### What is Integration By Parts? A 5 Minute Introduction

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Definition/Summary In this article, we shall learn a method for integrating the product of two functions. This method is derived from the 'product rule'…

### 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…

### Clarifying Common Issues with Indistinguishable Particles

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Commonly there is a lot of imprecision in talking about ''indistinguishable'' (or ''identical'') particles, even in serious work. This Insight article…

### A Formal Definition of Large-Scale Isotropy

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This Insight is part of my attempt to develop a formal definition of 'large-scale isotropy', a concept that is fundamental to most cosmology, but that…

### What is a Parabola? A 5 Minute Introduction

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Definition/Summary A parabola has many definitions, a classical one being, "A Parabola is the locus of all points equidistant from a given point (called…

### 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 of the electric utility company (public or private) may not…

### What Is a Limit of a Function? A 5 Minute Introduction

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Definition/Summary Limits are a mathematical tool which is used to define the 'limiting value' of a function i.e. the value a function seems to approach…

### Demystifying Parameterization and Surface Integrals

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Introduction This article will attempt to take the mystery out of setting up surface integrals. It will explain the basic ideas underlying surface integration…

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