Catapult Description of Magnetic Fields and Forces

McCall, Martin W. and Kinsler, Paul and Tymms, Vijay (2020) Catapult Description of Magnetic Fields and Forces. Physics Teacher, 58. pp. 416-417. ISSN 1943-4928

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Abstract

In many high school teaching materials the force on a current-carrying wire in a magnetic field is discussed using an idea based on a so-called “catapult field” (cf. Fig. 1), an engaging depiction of magnetic forces, albeit one which, to the best of our knowledge, has neither been used in college-level educational material or scrutinized in academic journals. Here we examine carefully the physical basis of the “catapult field” concept, and find both its accuracy and utility seriously questionable.