Class 7, 1/29/04,

3:13-3:53pm, Quiz 1
Many students finished early and Chau made the mistake of  saying the end of exam by 3: 43pm.. (The student, who was handing early and reminded Chau the mistake, ought to send Chau an e-mail. He well deserve bonus point.)

* No quiz on 2/4/04: During the break, while discussing the cycles of the quizzes which was intended to be two weeks in between, Emily King pointed out that according to the Syllabus there would be a quiz next Thursday! It was a mistake. (It is now fixed, by eliminating the one on 2/4/04 and redistributing the %. Hopefully, it is a happy solution for everyone.)

3:55-4:30pm, New items discussed:
N1: Cannon ball animations of the four distinct possibilities: falling back, orbiting, escaping at critical speed , and escaping over the critical speed. We will see that the possibilities of the fate of our universe following similar patterns, excluding the orbiting one.
N2: The commonly used approximate formula for potential energy difference of gravity, delta-(E_p) ~ Mgh at h<< (R_ea), was derived from the exact potential formula of gravity, E_p = - GM(M_ea)/r.


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Preview and Quiz 1 logistics

3:10-3:50pm, Quiz 1
Procedure: Please try to come early and please follow the rules specified in the Syllabus. All you need to bring is your favorite writing pen and eraser. (No calculator is allowed. Not only is it  not needed, it can slow you down. Also, only provided paper is allowed.)
1. Come to the front to pick up the exam papers, which are numbered. Please mark the number on the sign-up sheet.
2. The quiz has two pages, one on each piece of paper stapled together with the blank sides facing outside. Please do not look at the exam until everyone is ready.
3. When start, you can take the two pieces of paper apart and use the blank sides for calculations.  (If needed, there be more blank paper available at the front. No other paper is allowed, except the provided one.)
4. When done, please hand it in at the front, and make check mark on the sign-up sheet.
5. No quiz paper is allowed to be taken outside the class room.
6. Please do not discuss the content of the quiz, except with those you know for sure have taken it, till it is graded and given back at the end of the following Thursday class.

3:55pm-4:30pm
* Reiterate some items of the previous class.
* Hand out HW4.
* Start new chapters in TB1 and TB2.