Changing the Order of Newton's Laws—Why & How the Third Law Should be First

Newton's laws are difficult both for teachers and students at all levels.1–3 This is still the case despite a long history of critique of the laws as presented in the classroom. For example, more than 50 years ago Eisenbud4 and Weinstock5 proposed reformulations of the laws that put them on a sounder, more logically consistent base than is presented in many textbooks without resorting to “intuitional or anthropomorphic contrivances.”5 In 1990, Arnold Arons6 wrote that “the Law of Inertia and the concept of force have, historically, been two of the most formidable stumbling blocks for students.” One might imagine, therefore, that by 2012 remedial strategies would have resolved these difficulties, but there is little evidence that the problem has been satisfactorily addressed. Diagnostic tools such as the Force Concept Inventory7,8 have cast light on areas of difficulty; remedial strategies have included historical approaches, computer simulations, analogical approaches, and many more.9–12 Nevertheless, pap...