Lesson 12

PHYSICS LESSON 12 FOR
MONDAY, JUNE 21, 2010
I Introduction
II Logistics: Return of Papers, Running Grades, Turn in Assignments Due, etc. and
III Review of Lesson 10: Torque, Inertia
Torque, t = r F units in N m
“r” is the moment arm
Torque, t = I w
Inertia = characteristic of a body that resists change in direction or motion

IV Lesson 12: Gravitation
A. Johannes Kepler
1. Planets orbit Sun in ellipses (ovals)
2. Planets travel faster near the Sun, and slower far from the Sun
3. P2 = r3.
B. Isaac Newton
2. F = m a, F = m g; F = G m1 m2 /(r)2.

ge = - 9.8 m/s2.
gm = - 3.7 m/s2.
gj = - 26.8 m/s2.
gmoon = - 1.6 m/s2.

V Lab 9: Kepler's Laws & Orbits

VI Homework Set 4: due 6/24

VII Essay 3: Albert Einstein, due 6/24