Class 16, 3/2/04,
Highlights
* New about Mars had water at one time.
* We briefly reviewed what we did in the previous class about the Sun.
* Review for Quiz 3
    ** Looked at new additions to the web page, Guidelines to Exams and Quiz 3.
        *** Went over the exam study Pyramid
        *** Items to remember and understand for Quiz 3, besides those for Quiz 2.
        *** Looked at 10C5-8 and 10C9-10. ( 10C9 is for after Quiz 3; and 10C10 mainly gave a short summary of the current status of "the Theory for Everything".

* N1: From Pythagoras thm to Minkowski thm:

(See, TB1, Math-Insights: S2.1, p.441;  S2.2, p. 444; S2.3, P. 446;  S3.1, p. 460;  Figs. S3.9, S3.10, S3.12, and Special Topics "The Twin Paradox," p. 466 - 467)

    ** Pythagoras thm:
        r^2 = x^2 + y^2 + z^2    is an invariant under coordinate changes in space;
        p^2 = (p_x)^2 + (p_y)^2 + (p_z)^2   is also an invariant under coordinate change in space.

     ** Minkowski thm:
       *** The following quantities are invariants, not only under coordinate change in space, but also an invariant under constant moving coordinates.
         (d_M)^2 = r^2 - (ct)^2 , called Minkowski invariant distance squared:
                space-like: r^2 - (ct)^2 > 0;
                light-like: r^2 - (ct)^2 = 0;
                time-like: r^2 - (ct)^2 < 0

        M^2 x c^2 = p^2 - (E/c)^2:  rest mass is an invariant.


***********  Below was put up before the class. **************

Announcements:
1. Due to the fact that Mr. Tappel has over spent time for the course in the beginning of the quarter; from now on, Professor Chau will hold all the discussion sessions, as well as his office hour Wednesdays, 7:10-8pm. Let's all thank him for his good work. Teaching evaluation on his discussion sessions and office hours will be handed out in the coming discussion sessions. A couple students will be asked to deliver the package to the Physics Department right after the discussion sessions.

2. A hint to HW8, SA8.2, prompted by Dao Fan's question, is now posted in a link "Hint to HW8, SA8.2".

Class Preview
* Complete the connections among the following topics
    ** Minkowski thm
    ** uncertaity relations
    ** wave/particle property
* Wrapping up Chapter 15 of TB1 and Chapter 11 of TB2.
* Review for Quiz 3.



Please read the following before you fill out the sign-up sheet.

( Please try to review the class web page and have the answers ready before class.)

Sign-up items, Class 16, 3/4/04 
(1) Have you reviewed Guidelines for Exams & Quiz 3?   Y, or N.
(2) Have you reviewed 10C5-8?   Y, or N.
(3) Have you finished reading the reading assignments
  · Partial Our Star ; Read p.496-508 & summary pages (i.e., 15.1 to 15.3 and summary pages of  TB1).
  · Fig. 7.20 on p.186 and its explanations; Fig. 11.8 on p. 304 and its explanations.   Y, P (partial), or N.
(4) Initial.