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Spring 2008  Phys 5A  4/9  Lecture 2.9  50 minutes
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"Your work is to keep cranking the flywheel that 
turns the gears that spin the belt in the engine 
of belief that keeps you and your desk in midair."
--Annie Dillard 

TODAY (*.pdf)
Clicker homework

Ch. 8.7: The Motion of Rolling Rotating Objects 
     Ex: Falling Stick Derby 
         (cf. Comprehensive Problems 8.97, 8.98)
     Ex: Empty Can Derby 
         (cf. Conceptual Example 8.12, p. 282)
Chs. 8.6, 8.8: Angular Momentum Conservation (*.pdf)
     Ex: Conserved systems
         "Barbell twist," "The three dumbells"
         (School of Physics and Astronomy, University of Minnesota)
     Ex: Falling cats (start)
         Cat falling
         (YouTube.com)
         Governor Arnold Schwarzenegger and "cat"
         (Manipulated photo, Kattalogen)
         Rotating cats
         (icanhascheezburger.com)
         
NEXT TIME
Homework  
     Multiple-Choice Questions 8.3, 8.4 (for practice only)            
     Problems 8.61 (for practice only)
              8.62 (calculate initial K = K_tr,i + K_rot,i for (a),
                    then use energy conservation for (b))
              8.63 (for practice only)
              8.70 (to get units of kg*m^2/s, convert revs to rad)
              8.73 (for practice only)
              8.74
              8.75 (for practice only)
              8.78 (okay to keep final answer in units of rev/s)
              8.79 (for practice only)

Read Chs. 9.1-9.3
          (average pressure, atmospheric pressure, Pascal's Principle)
     Ch. 9.4
          (average density, Eq. (9-3): pressure at a certain depth)
     Ch. 9.5 
          (Eq. (9-6): gauge pressure vs. absolute pressure)