# The Theoretical Minimum

## What You Need to Know to Start Doing Physics

Book - 2013
A string theorist and a citizen scientist instruct lay readers on elementary principles of physics and associated math that amateur enthusiasts should know in order to study more advanced topics, in a reference that covers such topics as classical mechanics, electromagnetic fields and chaos theory--

"A first course in physics and associated math for the ardent amateur ... beginning with classical mechanics"--Dust jacket flap.

"A first course in physics and associated math for the ardent amateur ... beginning with classical mechanics"--Dust jacket flap.

Publisher:
New York : Basic Books, c2013.

ISBN:
9780465028115

046502811X

046502811X

Characteristics:
xi, 238 p. :,ill. ;,22 cm.

Additional Contributors:

## Comment

Add a CommentA fine introduction to classical mechanics. Don't be downhearted, the Lagrangian and Hamiltonian views of mechanics in fact serve to simplify and systematize the subject. They provide general methods for expressing and solving mechanics problems, where the usual freshman physics methods require you to figure out a new approach for every problem. Also, they are the only way to approach quantum mechanics so that you'll understand it. Another, shorter book with an introduction to this material and other ideas on a beginning level is "The Six Core Theories of Modern Physics," by Charles Stevens. One great thing about these books is that you can leave them laying around in public places, and nobody will steal them.

This book about "Classical Physics" and "classical mechanics" is an admirable attempt to give the layperson an introduction to physics which is "more than the Scientific American experience" and which is an alternative superior to the "childish anecdotes" ('t Hooft) imparted with physics textbooks written for high school students and for, say, premed college students. Still, it has some wrinkles which need to be ironed out with a new edition. For example, on p.77 it's claimed that "One condition for a local minimum is that the derivative of the function...is zero." But this claim about "a necessary condition" confounds the derivative of a function with the value given by that derivative---which is another function---when evaluated for some value of the domain. The function could be F(y)=y^3, in which case d/dy F(y)=3y^2. But 3y^2 does not necessarily take on a value of zero. The authors add to the confusion by claiming also that "d/dy F(y)=0" is "a sufficient condition" which "defines any stationary point". If so, then F(y)=c and there is no local minimum. Further, the 2nd derivative of F(y)=c is ALWAYS zero when the domain is the real numbers; it's never less than or greater than zero, as they imply it could be on p. 78. Again, the authors confounded the derivative with the concept of evaluating that derivative for some value of its domain. This is a strange mistake given that on p.113 they use the vertical bar to indicate the evaluation of a partial derivative at a specific value of the domain.

A more significant problem is the book's rush into the dungeon of determinism. It is, of course, important to recognize the importance of determinism in classical physics, but it doesn't follow that the teaching of physics should be restrained by the ball and chain of that philosophical error. In fact, the authors could have added to Lecture 1 an exercise in which the reader must write about and depict a dynamical law for the flipping of an ordinary coin in OUR world. Such an exercise would have directed the reader's attention toward the fact that the dynamical law of our world is not deterministic, at least in the sense supposed in classical mechanics, and the task of writing the details, subject to the limits of the reader's knowledge as it is in Lecture 1, would have provided a useful segue for later use when probability calculation becomes important to the physicist, and to the natural philosopher. The exercise would have called attention also to another important aspect of physics: It's preceeded by casual observation about regularities which everyone should notice and by attempts through philosophizing to arrive at a rigorous understanding of the dynamical law, or regularities, of our world.

It was difficult for me, but an excellent start. I'm rapidly discovering that physicists are truly "scientists" worthy of the name. And I have to respect anybody who calls out the popular madness of climate change.

This looks like a good read and John makes some good suggestions look for key word: Hamiltonian, Feynman,Lagrangian.

I had physics at cal poly in75 and it was cool. I watched, on you tube, a physics lecture at Stanford on string theory that was also cool. Looking forward to reading!

Hoax is a funny word to hear. Climate change is a political idea and science uses language more carefully than political scientists do. We all know that the most moronic way to motivate people is to scare or bait them. Wise people are not either scared (because they have courage) or tempted by the chance of gain (because they are moral), so lets not follow the crowd without thinking.

I'm not sure who this is really written for. They say for someone who wanted to take physics but had not. And thus a 'Minimum.'

I think a person would have wanted to have taken some basic course. Things like Lagrangian and Hamiltonian are really not even covered, as such, in university year long courses or even Feynman. Those who have taken these will find additional material and profit from this book.

Is this the same Leonard Susskind, particle physicist from Stanford, who believes climate change to be a hoax? (Admittedly, there are many financial hoaxes or scams affilated with climate change [cap-and-trade, carbon permits, etc.] which have nothing to do with actual climate change, but still....)

This book supplements Leonard Susskind's online Classical Mechanics lectures. To find the lectures, see: http://en.wikipedia.org/wiki/Leonard_Susskind#The_Theoretical_Minimum -- I would not recommend the book as a stand-alone physics text, but the Lecture and the book together are great. For anyone who is interested, the "Portland Math and Science" meetup group is currently (April 2013) organizing a study group for Classical Mechanics, partially based on Susskind's lectures: http://www.meetup.com/Relativity-Exploration-of-Portland/