Week 9: Tuesday 10/27/09 - Tuesday 11/03/09
P310/P510  Environmental Physics [You might attach this to the front of your homework.]
Ben Brabson

Weekly Assignment:
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Tues.   (10/27)     Ch. 9.1-9.6      The Generation and Use of AC Power             HW #6 due.
Thurs. (10/29)     Ch. 10.1-10.3   Superconductivity & AC Power Transmission
                             [regular class at 3:35 pm. After class, supper at Ben's House,
                             2000 Crandall Court, Hyde Park, Tel: 332-6507]

Tues. (11/3)         Ch. 12.1-12.6  Radioactivity and half-life
                           [No Tuesday Class Ben will be in Washington.]
Weds. (11/4)        Optional Review for Thursday's Test, here in our class room
                           8:00-9:00 pm.                                                                      HW #7 due.
Thurs. (11/5)        Test 2 [In Class in SW220]

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Homework #7: Due next Wednesday, November 4, 2009,
        Chapter 9: Exercises 9.3, 9.8, Problems 9.12, 9.13, 9.14, 9.15
        Chapter 10: Problem 10.2, and Special Problem #1 (below):
 
Special Problem #1
        An electric power plant generates power at 135 KV and delivers electricity over a pair of copper lines to a factory (with resistence Rload) 150 km away. The total cost of a 135 KV copper transmission system can be written in terms of the cross-sectional area of each of the two conductors a as $$ = A  + Ba  + C/a where A represents the fixed costs per km, B is the cost per unit area per km, and C approximates the I2R losses per km.  (It may help to think of this problem as a circuit composed of a battery (the power plant) and three resistors in series, the two wires and the load resistor at the factory.)
          a.) Find the cross sectional area, a, in terms of A, B, and C that minimizes cost, $$.  [Hint: It's useful to recall that an easy way to find the maximum or minimum of a curve is to take the derivative and set it equal to zero.]
          b.) If C = $600 mm2 km-1 and B = $500 mm-2 km-1, what is the maximum current that can be carried over a 150 km, two-wire minimum cost line? 
           c.) If the power loss, I2Rwire, is not to exceed 1% of the load, what is the power delivered to the factory?

News & Events:
1.) Physics - 4:00 p.m. Wednesday, Oct. 28, 2009 - Ivan Schuller, UCSD, Nanostructures: Confinement, Proximity, and Induced Phenomena.
2.) Geography - 4:00 p.m. Friday, Nov. 6, 2009, SB150, Timothy Bartley, Socio, IUB, Transnational Private Regulation in Practice: The Uneven Implementation of Labor and Environmental Standards.
3.) Geology - 4:00 p.m. Monday, Nov. 2, 2009, Mike Prentice, UGS, The Response of Ice Sheets to Climate Change: A Geological Perspective about the West Antarctic Ice Sheet.