Caltech Physics 1b Newsletters 1976

 

Drinking from a firehose! That's what an undergraduate education at Caltech was like. Freshman physics was one of the first such libations that students experienced. In early 1976 I was a graduate teaching assistant responsible for a discussion section in Physics 1b, the winter term where dazed young people learned about mechanics (both statics and dynamics), harmonic motion, vibrations, waves, and so forth. Walter Bright was assigned to my section; he's now a software developer. Recently Walter sent me copies of some of the materials he saved from his studies three decades ago. Among them were four "newsletters" that I semi-diligently typed (on a manual typewriter!) and photocopied to give to my students.

Frankly, I don't remember much of that year—I had yet to meet Paulette, my wife-to-be. Apparently, however, my writing style was already well-established. The "newsletters" include encouraging remarks directed at the students, feeble self-deprecating attempts at humor, exhortations to persevere, tips on problem-solving, and random physical-philosophical asides. Some excerpts follow. Click on the links to view the scanned PDF documents themselves.

from Caltech_Physics_1b_1976-01-19.pdf

I'm almost out of space, so will make other comments in class or in next newsletter. One item: David Finkelstein, who's fairly famous in the field of relativity, is giving a seminar at 4pm today, in 114 Bridge. It will probably be incomprehensible to me, but these things are good to go to, for entertainment & culture ... you're all invited ...

from Caltech_Physics_1b_1976-01-26.pdf

I'd like to apologize for my lousy performance Wednesday ... my only excuse is that I got up at 5:30 am that day for a T'ai Chi Ch'uan class ... and since I'm going to be doing that for the rest of the term, maybe it would be best if you'd all skip the Wed. session. ...

I'll bet this was a pretty tough quiz for most people, though if you just stayed calm & conserved E & p and recalled that E2=p2+m2, you got it all via a little algebra. After grinding it out, I saw how simple-looking the answers were for b), c), & d), so maybe there's a clever trick whereby you can leap to the answer at once ... but I don't see it yet. The orthodox route goes as follows: ...

Other remarks: looking at last time's homework, I noticed that most people chose to solve the first problem by solving for γ and then grinding around...this works, of course, but using E2-p2=m2 is much quicker & easier. One reason that that equation is so nice is that it defines an invariant, m. Rest mass m is the same, no matter what coordinate system you use, what velocity you're moving relative to the system, etc. E certainly depends on the observer's state of motion, and so does p; by going to the center-of momentum frame of the system (if one exists), you make ptot=0, for instance. But m is independent of all that.

The search for coordinate-invariant things tends, historically, to have been very productive—it was the philosophical motivation that lead Einstein to general relativity, for instance. The beauty & power of vectors is due to the fact that they let you make general, coordinate-free statements about things, like "F= dp/dt", true no matter how you happen to choose your x, y, and z axes. Coordinates are artificial, a human construction; they're very useful for doing particular calculations and for crunching numbers in a computer, but they don't exist in Nature, and the real physics of things must be the same no matter what coordinates you take.

Enough philosophy ... I'll fill out the rest of this page with some good formulæ that we've seen recently: ...

from Caltech_Physics_1b_1976-02-02.pdf

I was shocked at the lecture last Friday, until I realized that it was only supposed to be a preview of coming attractions, and wasn't supposed to be teaching anything much. The first 2 chapters of FVW are that way, certainly. ...

For the quiz: it's really all stuff we've done before. ...

Comments on the homework assignment: it's all mathematics this time, some of it cute, but not terribly exciting. You should be able to do the stuff, in order to be able to solve problems. ...

I have some space left, so I'll fill it with mathematical data that's valuable to know. Again, I remind you that I'd be happy if you would come by my office or room, any time, especially to talk about physics. If I'm trying to work, I can set up a time to meet when I'm less busy. ...

from Caltech_Physics_1b_1976-02-25.pdf

First, a variant on the last quiz. So many people misunderstood what physical system was being described, with those massless frictionless rings at each end, that I marked down a special symbol in my records & didn't really grade their quizzes. If you want to, consider the following problem: ...

Quiz above is open books & notes, but do LIST ALL REFERENCES USED, and if you run across this problem in some book, don't read any farther. No time limit, but don't spend more than an hour or two...it's not worth the effort. No consultation with others until after you're done working. Another problem, for extra credit & fun: ...

Other news: I'll be going to Palomar to fool around, Saturday-Tuesday, and on Wednesday next there's a boat trip to Catalina for the SCUBA class ... so, Rich Flammang will be taking over Mon/Wed at 3 for me. He's in the same office as I am, so if he forgets to show up, please try to remind him. Turn in the quiz & bonus question by Friday afternoon if you want it back early; I'll leave graded things in my TA mailbox.

Supplementary comments for you math freaks: ...

(Many thanks to Walter Bright for his kindness and charity in preserving and sharing these historical documents! cf. CollegeCollage3 (2001-09-29), ...) - ^z - 2009-11-16