Numbers

The Three Laws of Motion

1. An object will remain motionless or will move in a straight line unless acted upon by a force
2. The acceleration of an object is directly proportional to the force acting upon it, and inversely proportional to the object's mass
3. For every action, there is an equal and opposite reaction

“Shortly after sending 'Motion' to Halley, Newton began work on the treatise for which he is most famous, 'Philosophiae Naturalis Principia Mathematica' ('Mathematical Principles of Natural Philosophy') usually known simply as the 'Principia.' This is where, among many other insights and discoveries, he articulated his three laws of motion, which students still learn in high school physics. He explained that gravity causes tides, and that the gravitational force of Jupiter perturbs the orbit of Saturn.”—Olivia Judson, “The Ten Days of Newton,” The New York Times, December 23, 2008.

How It's Used

"The present debate is focused on the esoteric concept of there being a fundamental difference between principles and rules. In the red corner the call is for very broad statements of policy which would allow a wide interpretation of the appropriate application of accounting principles to each situation. In the blue corner is the demand for extremely detailed rules, sometimes called the cookbook approach, which entirely eliminates the exercise of judgment in the preparation of financial information...

"Those in the blue corner want a detailed set of rules for every situation. This could never be achieved. Sir Isaac Newton managed to describe the majority of physics with three laws of motion. Push the rule book to its limits and you'd need a complete description of quantum mechanics and relativity—a combination which is likely to be incomprehensible to most users."

"When Isaac Newton (1642-1727) finally found the answer and expounded it in his three laws of motion, 2,000 years of theories were promptly overturned, and the course of human history was changed. The laws proved so durable that now, three centuries and several scientific revolutions later, they still explain the mechanics of the ordinary visible world with superb accuracy.

"As a result, no basic physics course is complete without a thorough explanation of the laws—especially the second, usually expressed as F=ma. That is, force equals mass times acceleration. Increase any of those three things, and the term or terms on the other side of the equal sign will increase, too. So, for example, if you want to accelerate a mass twice as fast, you must push it with twice as much F. This Second Law lets you calculate precisely how to send a space probe to Jupiter, how to build a roller coaster, how much braking power you need to stop a Buick on the Beltway or how fast your poodle will fall if you pitch it out the window."

"Dance: Ups and Downs. Bodies and apples will be sailing through the air this week at Yerba Buena Center for the Arts Theater, where the Lawrence Pech Dance Company will premiere choreographer Julia Adam's ballet 'Newton: Three Laws of Motion.' Performed by eight dancers to music by Bach and Mozart, played live by a chamber orchestra featuring soprano Marnie Breckenridge, the piece will deal with the gravity of the situation."

"Last November, while the world's attention was focused on Iraq, thieves stole a rare first edition of Isaac Newton's Philosophiae Naturalis Principia Mathematica from the Russian National Library in St. Petersburg. A few weeks later, police announced its recovery to an uninterested world. Principia, first published in 1687, is a key work in modern science. In it, Newton proposed the three laws of motion and the law of universal gravitation, foundations of physical sciences and engineering.

"Less well-known is Principia's final chapter, in which Newton expounded on his beliefs: 'This most beautiful system of the sun, planets and comets could only proceed from the counsel and dominion of an intelligent and powerful Being, . . . eternal and infinite, omnipotent and omniscient. . . . He governs all things, and knows all things that are, or can be done. . . . We adore Him as His servants.'"

"Back home, that first irony-free evening, I found myself telling Dan a raft of antiheroic stories about my childhood, stories I’d never told him, I realized, because I felt insecure...

"For the next few weeks, even our sex was more intimate, more open and trusting. Then I found myself recoiling. As if I were obeying Newton’s third law of motion, I had an innate equal and opposite reaction to our newfound intimacy, to living our lives, as the saccharine marriage-improvement phrase goes, as we instead of as me. I loved the idea of digging out of my emotional bunker and going over to Dan’s to live with him. And I liked being there, for a while. But Dan has a bigger, flashier personality than I do. I feared, in our intimacy, I might be subsumed."

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