April 20th, 2009

In class we:

• 1) Went over the test: Circular Motion, Work, & Energy.(Ms. Kozoriz posted the corrections.)
• 2)Went over the remaining textbook problems: Chapter 8, Page 172, Questions 1-5 and 9-12.

The answers were:

i. Tj = 12 years
ii. 3.83 x 10^-3
iv. 4.23 years
v. Ts = 0.35 Tm
ix. Fg = 8.8 x 10^-10 N
x. Fg = 6.5 x 10-8 N
xi. a) Fg = 3.13 x 10^26 N
b) Fg = 490 N
xii. m = 9.01 x 10^-21 Kg

• 3) Handed out notes: Gravitational Potential Energy.
• 4) Started a question sheet: Gravitational Potential Energy Questions.
• 5) Started another question sheet: Chapter 8 Review
• 6) Discussed the Gravitational Potential Energy Well:

-Ep = mgh (holds true for small heights)
-Ep > 0, positive value, above ground level
-Ep = 0, at ground level
-Ep< 0, negative value, below ground level
For shorter distances:
-Fg = Gm1m2/R^2
-Vector
-Inverse Square
-F α 1-R^2
-Force, measured in Newtons, N
For greater distances:
-Ep = Gm1m2/R
-Scalar
-Inverse
-E α 1/R
-Energy, measured in Joules, J