- the last part of “Why Mathematics Is So Effective in Physics”, and
- the second half of the lecture on the principle of least action.

Then we’re going to work out some problems in class using the principle of least action, also called Hamilton’s Principle. This will involve correctly setting up the Lagrangian for each problem and working out the equations of motion using the Euler-Lagrange equations. We will work these problems out in detail, omitting little algebra. I’ll try to have hardcopies of this material available at class time.

Then we’ll take up Lecture 7, Symmetries and Conservation Laws. In this lecture Susskind defines symmetries and shows how they lead to the conservation of various quantities. Near the end of the lecture we’ll work on a few problems, just as we did above.

Assignment: **Read Lectures 6 and 7 in the book. If time allows, view Lecture 3.**

We’ll try to cover

- Interlude 3, Partial Differentiation, which includes extrema,
- Lecture 4, Systems of More Than One Particle, which includes momentum and phase space, and
- Lecture 5, Energy.

If time allows we’ll begin Lecture 6 from the book, where formal classical mechanics really starts. If we do begin this, I’ll keep it self-contained so you needn’t read ahead (unless you’re so inclined). You should consider reading Lecture 6 in the book and viewing Susskind’s Lecture 3 **before our fifth class**, on October 21, 2013.

- finish differential calculus, covering the short topic of Composition Rules;
- discuss the
**kinematics**of motion, that is, the quantities we use to specify the path an object takes in regular, physical space; - discuss integral calculus, which is how we compute the area under a curve; and hopefully
- begin particle
**dynamics**(the real beginning of physics), which comprises the rules that tell us how forces control motion.

Completing dynamics will take us through the end of Lecture 3 in the book (page 73 in the hardcopy version), so you should take a shot at reading that far. We will still be in Susskind’s 2nd lecture. If your time allows, viewing or reviewing that lecture should be helpful.

The next worked exercises will cover particle dynamics and partial differentiation. I’ll try to have those posted by the next class time (October 7) or shortly after.

]]>If you go to the bottom of the **Resources** page, you’ll find a link to a set of solutions posted by George Hrabovsky, the second author of our text. (Thanks to Gladys for reminding me of this.) I have trouble viewing his pdfs for unknown reasons and I’ve only hacked my way through a few of them. You may have better luck than I did.

If you have questions or comments about either my solutions or Hrabovsky’s, be sure to raise them in class.

]]>I’ll try to get through Lecture 2 (differential calculus and motion) before the week is out.

If you find some possible errors let me know. If you do it by commenting on this post, it will let all of us share in the discussion. Don’t be shy about raising topics you find confusing; others probably feel the same way.

]]>I took the course the first year the textbooks were in print. They were different from any physics text I have seen before or since: insightful, entertaining, and hard on undergraduates. My later impression was that the books were personally very popular with physicists but were not widely used as texts because of their difficulty.

The first volume of the series, which covers mechanics, is now freely available on the Internet at http://www.feynmanlectures.caltech.edu/. The first three chapters include his overview of physics as of 1963, which is not radically different a half-century later (so far as I know). Chapters Four through Fourteen cover mechanics and are interesting to sample; note particularly Chapter Eleven on vectors. Chapter Sixteen, Section One, has his famous complaints about “cocktail-party philosophers.”

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