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Spring 2008  Phys 5A  2/29  Lecture 1.15  50 minutes
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"When love is gone, there's always justice.
And when justice is gone, there's always force.
And when force is gone, there's always Mom.
Hi, Mom!"
--Laurie Anderson

TODAY (*.pdf)
Clicker homework

Ch. 4.4: Newton's Third Law
     "POF-OST-ITO" (recognize and utilize)
     Ex: Problem 4.50
          N1 and N3 pairs
     Ex: Comprehensive Problem 4.127
          Properties of scales, pulleys, and using N3

Problem-solving session
     Problem 4.54
     Work together in groups of three or four (suggested)
     Enter numerical answers using own clicker before leaving

NEXT TIME
Homework 
     (Study Fig. 4.26, p. 105)
          Find **magnitudes** of x, y components of force _F_ (*.gif)
          (Hint: use F*cos(theta) or F*sin(theta), or vice versa; neglect 
           +/- signs, and take each theta angle as drawn in each situation)
          
          Is there a general rule of thumb to when cosine or sine applies?
     
     Problem 4.68
     Comprehensive Problem 4.128