Physics 161 General Physics
Mechanics and Particle Dynamics

Spring 2009
Sections 0301-0306

1. Here are the finals solutions
2. So, we are grading the finals ... Eric is grading SA#1, I am grading SA#2, and Mike is grading SA#3. I think I should be able to submit final grades on Wednesday. So, look out for that. You should be able to see updates on Blackboard before Wednesday.
   Good luck on your remaining exams
   And yes, it was wonderful having all of you in my class this semester. Have a great summer.


3. David Hammer wrote up a review sheet for rotational motion that might help you: [LINK] And of course, you have the review sheets from the previous exams: #3, #2, and #1


4. Third exam from Dr. Mohapatra [PDF] Some notes
   • For Q1: Notice that the T1 and T2 cannot be equal if the pulley (with mass) has to rotate. (Just, think about it: if you wanted to rotate a real pulley you would pull harder one side - that is exactly the case here)
   • For Q2, the last subpart, interpret the "final velocity of the entangled system" to be: If the two blocks got stuck after collision, what would be the velocity of the entangled system immediately after the collision
   • For Q3(a), assume that the hollow cylinder has very thin walls, so it's moment of inertia is just that of a hoop. Don't worry too much about Q3(c) if you don't get that.
   • Finally, here are the solutions [PDF]


5. Solutions to HW 10 [PDF] -- Questions 5 and 6 are on angular momentum that we have not really talked about (we will on Monday), so anything you do on those gets full credit. Take you best shot at questions 1-4 before reading the solutions.


6. David Hammer has posted two useful notes -- (i) on the moment of inertial and kinetic energies of Ring and Disk [LINK] and (ii) on connecting how engineers and physicists define moment of inertia [LINK]


7. Information on Finals: (1) The Finals would be held in Room 0131 of the Armory on Friday, May 15th, from 6:30pm-8:30pm (2) You are allowed to bring in one page of notes (3) Still no calculators! (4) 8 Multiple Choice and 3 Short Answer questions


8. EXAM3 results are in: There was a healthy increase in the class average. The average was 28.25 ...about 56.5%. I would like it to be higher still in the finals. The Solutions to the third exam and information on the grading.


9. I have finally gotten around to writing the solutions to Dr. Mohapatra's midterm exams. There is one more exam from his class and I will post that soon. Here are the solutions -- but remember looking at the solutions helps if you have already worked on the exam on your own first.
   [Exam 1 solutions] and [Exam 2 solutions]


10. Course Evaluations: Please take a moment to fill out the online course evalutations. Click here It helps us improve our teaching best if you are specific about what worked for you and what did not.


11. Assignment 10 is not due this Friday. It is due the coming Monday - so you have a few more days to finish it.


12. Assignment 10 is posted [PDF] Note: The assignment is due Monday, May 11th


13. There are interesting simulations on the web for forces on a pendulum bob as it swings, or for energy and momentum in various collisions or on a roller coaster. These could help build intuition about energy and momentum. Some great simulations are provided by University of Colorado, Physics Education Group. They are fun as well as informative. If you generate questions during your explorations, do feel free to come talk to me.


14. Information on Finals: The duration of the final is 2 hours (Friday, May 15th, from 6:30pm-8:30pm) The finals would have 8 multiple choice questions and 3 short answer ones. The short answer questions would be similar to the questions on Dr. Mohapatra's exam or to Q 5,6 on our exam 2 and Q6 on our exam 1.


15. Prep for Finals: The finals would be common for all sections of 161 - across all professors. The final exam would be comprehensive and have questions contributed by the different professors. So, it might be good for you to practice problems from another professor. Here are the first two exams from Dr. Mohapatra. [First Exam (pdf)]    [Second Exam (pdf)]
    Note: On Exam1, Q3, Radial acceleration refers to the component of acceleration perpendicular to velocity, and tangential acceleration refers to the component along the velocity.


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