2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/106593I discuss how to estimate the gas mileage of a car. This discussion, which covers air resistance and Reynolds numbers, describes one way to introduce dimensional analysis and order-of-magnitude physics into introductory physics (if only the syllabus would allow it). It is part teacher's guide and part textbook chapter -- I hope not the worst parts of each.plain TeX with eplain, 12 pages, 4 figures, free/open-source license (OSL 3.0); based on a talk at the 121st AAPT National Meeting, Guelph, Ontario, 31 July 2000 (see http://www.aapt.org/AbstractSearch/FullAbstract.cfm?KeyID=8454)Physics Educationtext