Lecture 5.

A. Aurora Watch!*

B. Class Business: Homework Questions, Reading for Wed. - thru Ch. 3

C. Wednesday Muddiest point: parallax - activity!; retrograde motion & epicycles*

One Hint: In homework #1, question #8, you're asked to compare the force on Mir, with that at the Earth's surface. The Earth's surface is 6,500 km from its center, on average.

D. Tycho Brahe makes precise astronomical measurements* for about 20 years -- see image, p.42

E. Kepler's Laws Match Tycho's Data*

F. Newton's Laws*, and their Application*

G. Bare Bones Physics Study Guide*