Classical Physics Articles

Classical physics deals with phenomena we can experience and manipulate directly, with a minimum of apparatus. There are new developments in classical physics all the time.

In some cases, “modern” physics (now almost 100 years old) provides a stronger foundation for classical phenomena: the color of copper, for example. In other cases, modern physics explores physical phenomena outside of our daily experience- the very fast, cold, small, or large.


physics cannonball projectile

Maximizing Horizontal Range of a Projectile

Introduction A recent homework problem that appeared in the forums was concerned with maximizing the horizontal range of a projectile subject to the launch…
mechanical conservation of energy

Why Bother Teaching Mechanical Energy Conservation?

Note: It is assumed that the reader has read part I and part II of the series.Is Mechanical Energy Conservation Free of Ambiguity? Can We Do Better…
energy conservation can we do better

Can We Do Better Than Mechanical Energy Conservation?

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…
elastic ball collision

An Alternate Approach to Solving 2-Dimensional Elastic Collisions

Introduction This article follows on from the previous on an alternate approach to solving collision problems. In that article, we determined the equal…
energy conservation ambiguity

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

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. …
Mass Generation

An Introduction to the Generation of Mass from Energy

Introduction This article is essentially an addition to the previous one on (mainly) inelastic collisions to include the particular case of inelastic…
Collision problems

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…
Diffraction Grating Spectrometer.

Learn the Fundamentals of the Diffraction Grating Spectrometer

Introduction In this article we will discuss the fundamentals of the diffraction grating spectrometer.  The operation of the instrument is based upon…
Conservation of Spin Angular Momentum

Exploring Bell States and Conservation of Spin Angular Momentum

In a recent thread, I outlined how to compute the correlation function for the Bell basis states\begin{equation}\begin{split}|\psi_-\rangle &=…
Bohr’s Helium Lines

Understanding Bohr’s Helium Lines

Introduction In a previous article "Calculating the Balmer Alpha Line" we mentioned how accurate predictions of the spectral lines of singly ionized Helium…
what is impedance

What is Impedance? A 5 Minute Introduction

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]…
Learn Dimensional Analysis

Learn the Basics of Dimensional Analysis

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…
Balmer Alpha Line

Calculating the Balmer Alpha Line: Atomic Hydrogen

Introduction Most readers acquainted with the hydrogen spectrum will be familiar with the set of lines in the visible spectrum representing transitions…
What is potential energy

What is Potential Energy? A 5 Minute Introduction

Definition/Summary Potential energy is simply another name for (minus) the work done by a conservative force.Since the work-energy theorem states…
Moment of Inertia

What is the Moment of Inertia? A 10 Minute Introduction

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

Exploring the Spectral Paradox in Physics

In terms of wavelength, peak solar radiation occurs at about 500 nm.  Interestingly, this is well within the range of human vision.  When solar radiation…

Permanent Magnets Explained by Magnetic Surface Currents

Introduction: The purpose of this Insight is to explain permanent magnets in a way that is in agreement with advanced textbooks on the subject, and that…

Fabry-Perot and Michelson Interferometry: A Fundamental Approach

Fabry-Perot Effect: The Fabry-Perot effect is usually treated in most optics textbooks as the interference that results from multiple reflections of the…

Learn The Basics of Rolling Motion

Although rolling wheels are everywhere, when most people are asked "what is the axis of rotation of a wheel that rolls without slipping?", they will answer…

Why Road Capacity Is Almost Independent of the Speed Limit

Let us start with a familiar situation. Take a familiar part of a road, for example, the one from your home to work. How long will it take you to drive…

Elementary Construction of the Angular Velocity

Physics books seldom contain an accurate definitions of the angular velocity of a rigid body. I believe that the following construction is as simple as…

Introduction to the Secondary Forces in Physics

Many are familiar with the "fundamental forces" of nature: gravity, electromagnetism, and the strong and weak nuclear forces. Three of these have a tendency…

Exploration into the Physics of Rainbows

For several years, I have been contemplating this beautiful picture by photographer Brian McPhee.  I have a personal interest in the photograph because…

Do Photons Move Slower in a Solid Medium?

This question appears often because it has been shown that in a normal, dispersive solid such as glass, the speed of light is slower than it is in a vacuum.…

Exploring a Paper on Scaling Laws and the Speed of Animals

Introduction In a recent issue of the American Journal of Physics, I read an interesting paper by Nicole Meyer-Vernet and Jean-Pierre Rospars examining…

Frequently Made Errors: Pseudo and Resultant Forces

  1. Real versus Fictitious Pseudo, or "fictitious", forces can arise when a non-inertial frame of reference is used. Using a non-inertial frame…

Learn the Physics of Hand-to-Hand Combat

Civilizations wax and wane but principles of physics remain steadfast. The most effective techniques from martial arts are ones that effectively dole out…