Author Archives: BruceSherwood

A 10-minute video summarizes this article: tinyurl.com/AFlatEarthModel A one-hour physics colloquium based on this article. 50-minuta versio tinyurl.com/PlataTero, kun partopreno de Derek Roff. In the US and in Britain there are organized groups of people who strongly believe that the … Continue reading →

Consider the following interaction between a proton and an electron: The electric forces between the proton and electron exhibit “reciprocity.” That is, the electric force that the proton exerts on the electron is equal in magnitude and opposite in direction … Continue reading →

People sometimes ask, “What is the source of the energy expended by a magnet to attract another magnet, giving it kinetic energy? After all, the magnet doesn’t get colder.” The energy aspects of a magnet accelerating another magnet can indeed … Continue reading →

Because the magnetic force on a moving charge is perpendicular to the velocity, the work done by a magnetic force is zero. However, in a multiparticle system it can happen that magnetic forces can rearrange the energy within the system, … Continue reading →

A colleague identified a puzzle concerning Faraday’s law. A circular loop at the center of a long solenoid with time-varying magnetic field will run a current due to the emf, which is the path integral of the (curly) non-Coulomb electric … Continue reading →

Here is a time line for the development of VPython, an extension to the Python programming language that makes it unusually easy to generate navigable real-time 3D animations (vpython.org). 1997: While at Carnegie Mellon, after writing a volume on introductory … Continue reading →

I have a story to tell about pseudowork, the integral of the net force along the displacement of the center of mass, which is different from the true work done by a force on a system, which must be calculated … Continue reading →

In 1966-1969 I was active in an experimental particle physics group at Caltech and taught intro physics using the Feynman Lectures on Physics as the textbook, which was a fantastic experience. I often saw Feynman at lunch in the Caltech … Continue reading →

David Hestenes’ goal for geometric algebra is to subsume under one umbrella many different kinds of mathematics used by scientists and engineers (see https://davidhestenes.net/geocalc/GA_Primer/GA_Primer/, https://davidhestenes.net/geocalc/html/IntroPrimerGeometricAlgebra.html, and https://davidhestenes.net/geocalc/pdf/PrimerGeometricAlgebra.pdf). The key to this unification is to provide powerful geometrical representations for all … Continue reading →

A talk given at a Santa Fe Science Cafe, 2013 Jan. 16 Abstract of the talk Video of the talk Interview on KSFR radio (15 minutes; choose the 3rd audio option) The great discovery by Maxwell about 150 years ago … Continue reading →