Week 5-Bill Murray Day ---Groundhog Day--I mean, Feb. 2. Bill Murray Day ---Groundhog Day--I mean, Feb. 2. Bill Murray Day ---Groundhog Day--I mean, Feb. 2

Exam 1 Friday --

"How can you have any pudding if you don't eat yer meat"

"Well, what if there is no tomorrow? There wan't one today?

Exam comments were posted last previously

HW-comments---again, questions, questions, questions, group work. Remember it is 40% of course grade!

Ch. 6 hw-- Anticipate due--Friday Feb. 13th---(will there be another one in March).

Given the temperature of the universe is 2.7K (microwave background from big bang). 
a)    What is the Intensity of light put out by the universe as a large blackbody
b)    Further given that I(total)=c/4*(Energy density), determine the photonic energy density just due to the background emission?
c)      Now use the radius of the universe as 18 (or is it 13.....something) billion LY to determine the total energy due to the background light, and determine the corresponding mass equivalent.

Ideas for cyops:

Here is a thought for cyop if you wish---make it your own----Take a being (yourself, Klingon, Xindi, Gungan, Dug, Vogon, or other species--Vorlons, ET, Wall-E, Yoda, ) ----and dump them outside the airlock of your spaceship (in deep deepest darkest space). You wish to calculate their initial rate of change of temperature due to radiative heat loss (there is no other heat loss here). You might assume they are in a special spherical space suit, blenderized, and stirred (not shaken) sufficiently to maintain a uniform body temperature. You may further want to assume that we are all mostly sacks of water. You are finding the initial dT/dt. You will need certain initial assumptions. If you wish to go deeper it is possible to find dT/dt in general (solution to diffeq with given assumptions --model building).

YOU are a lightbulb. What is your wattage? (You may need to know the surface area of your skin--please consult with Buffalo Bill/Jame Gumb).

What would your temperature need to be if you were to radiate 1.21 GW of power?

You have a standard incandescent lightbulb. What fraction of the power is emitted in a 1nm range at say 5microns?

 

 

Looking ahead. (dates TBA)


Ch 7--problems 1, 2, 7, 9, 15    TBA
 

Ch. 8 --problems 2,4, 5, 7, 14 (you should ask lots of questions on 14), 17, and 25. TBA


Ch. 9     4, 13, 15, 16, 27 TBA

 

Test 1 things to know-Posted previously---------