Preflight assignment 4


(Closed. Preflights are due at 10 AM on Tuesdays.
When you are satisfied with your response, you must click the SUBMIT button at the bottom of this page.


  1. Go back over the steps in Taylor section 1.5, on "Multiparticle systems" (p. 20 and 21), which proves conservation of momentum, for the specific case N=3 (i.e, there are particles labeled 1,2, and 3 making up the system). Write out all the summations in Eq 1.27 explicitly (i.e, no "summation" symbols, really show what is being added up!) to make sure you understand the somewhat mathematically formal manipulations going on. In the space below, summarize. (Ex: My ASCII notation for "the force of 1 on particle 3" might be "F13", and F(external) on particle 2 might be "Fext,2")




  2. Look at Taylor Example 3.1 Suppose in that figure, velocity v1 = (+1,+1) m/s, and v2=(1,-2) m/s.
    Suppose further that m1=2m2.
    What is the angle between the final velocity of the final "blob" (v), and the initial velocity labeled v1?





  3. Look at Taylor's Example 3.2. Explain in your own words why Taylor says "For any given z, the integral over x and y runs over a circle of radius r=Rz/h". (Specifically, we're curious where that Rz/h came from! )
    ALSO, explain in your own words how we know Y(center of mass)=0 (Please don't just say "by symmetry" - be a little more explicit!)



  4. Please submit a question you have about the reading assigned for the upcoming class. What seemed hard, was something confusing, what would you like us to spend class time on? If you can't come up with any question, how about a comment - (did anything strike you as interesting? )
    Reminder: the reading assignments are on our course calendar


    Thanks for your time.