Homework policy, assignments, and
TAM 203, Spring 2006
Homework policy: To get credit, please do the things listed below on every homework.
a) Homeworks are due at the start of lecture 7 days after it is assigned (at Spring break it is due one week later). You need not bring your homework to the front of the class, hold on to it. It will be collected from the class at the start of class. Homework handed in after the start of class or later will be marked "late." For example, you should have the first homework assignment (assigned January 24) in hand at your seat, following the policies below, at the start of lecture on Tuesday January 31. The second assignment is due Thursday February 2, etc.
b) On the top right corner neatly print the following, making appropriate substitutions as appropriate:
HW probs 1-3, Due January 31, 2006
Section 1 at 12:20
TA: Mary Liu
b) STAPLE your homework at the top left corner.
c) At the top clearly acknowledge all help you got from TAs, faculty, students, or ANY other source (but for lecture, text and section). Examples could be "Mary Jones pointed out to me that I needed to draw the second FBD in problem 2." or "Nadia Chow showed me how to do problem 3 from start to finish." or "I basically copied this solution from the solution of Jane Lewenstein " etc. If your TA thinks you are taking too much from other sources he/she will tell you. In the mean time don't violate academic integrity rules: be clear about which parts of your presentation you did not do on your own. Violations of this policy are violations of the Cornell Code of Academic Integrity.
d) Every use of force, moment, momentum, or angular momentum balance must be associated with a clear correct free body diagram.
e) Your vector notation must be clear and correct.
f) Every line of every calculation should be dimensionally correct (carry your units).
g) Your work should be laid out neatly enough to read by someone who does not know how to do the problem. Part of your job as an engineer is not just to get the right answer, but convincingly so. That is your job on the homework as well.
h) Some problems may seem like make-work because you already know how to do them.
If so, you can get full credit by writing in full "I can do this problem but don't feel
I will gain from writing out the solution". You can keep doing this unless/untill your grader/TA challenges your self-assessment.
i) Computer work should be well commented. At the top the computer text file should include your name which you
later highlight or circle with colored pen. Part of any computer output should also include your name, printed by the computer. Also highlight this or circle it with colored pen.
BONUS PROBLEMS: Numbered I, II, etc. Each problem is worth a full homework assignment, not just one homework problem, if you send a solution before a solution is posted. This adds to your homework score. Solutions must be clear, authoritative and complete (e.g., not speculative) in nature. The document must be self-contained. That is, what you send in needs to be clear to an intelligent reader who has not read, and is not going to look at the book or any other sources. For example, the solution needs to include a coherent description of the question that is being answered. A student should learn from your solutions as should a professor. The reasoning should be sufficiently clear that there is no argument about whether or not it is correct. Please do not put your name on your solution. Send pdf scan of a clear solution to firstname.lastname@example.org and your TA. Send copies of any correspondence you have about bonus questions to your TA. If your solution is not good enough you will be given a chance to improve it. You may discuss the problem, or improvements to your solution, at office hours.
WRITE-AN-EXAM-QUESTION BONUS: Due May 8. Write from 1 to 5 candidate final exam questions. Write clear complete solutions. Hand writing and clear hand-drawing are fine. These cannot be taken from any books or from any old exams. Questions can be of any style that you think is appropriate (even multiple choice or essay, if gradeable). If appropriate, they may be the basis for actual final exam problems. Send pdf scan to email@example.com and your TA.
Problems are from TS (Tongue and Sheppard) unless otherwise specified (as BJ, Beer & Johnston STATICS, or RP, Ruina & Pratap DYNAMICS)
January 24 Tuesday (due Tuesday January 31, see policies
1) Please read the homework guidelines at the top of this WWW page. Write "I have read and I understand the homework guidelines."
2) BJ 4.81, pg 189, L-shaped rod w/ pivot, pulley and force.
January 26 Thursday (due Thursday Feb 2): Solution
Bonus I) Assume in text sample 2.3 that the acceleration increases linearly in time from a=0 at t=0. Then you can calculate the average acceleration explicitly and compare with the solution in Eq 2.18. Why the disagreement? Note that formula 2.17 in the text is an exact formula that does not depend on acceleration being constant. So there is an apparent paradox that your solution for non-constant acceleration does not agree with the book solution. What is the resolution of that paradox? (Solution)
Bonus II) In text sample 2.10 find a smaller muzzle speed that gets the golf ball through the window. What is the mistake in the reasoning in the text? (Solution. This is good enough, although a problem restatement at the start would make it better. Submissions still accepted.)
January 31 Tuesday: Solution
February 2 Thursday: Solution
10) BJ 4.114 (Just find the tension in cable EB).
February 7 Tuesday: Solution
February 9 Thursday: Solution (slightly
Extra reading about moment and moment about an axis: PR 2.3 (pgs 32-49 pdf 50-67).
17) RP 4.87 (pg 746 of problem book, pdf page 27), Just find the tension in cable AB.
February 14 Tuesday: Solution
Extra reading: PR Chapter 5.1 ( pages 217-232, pdf pages 235-250)
February 16 Thursday: Solution
24) RP 4.65a (pg 743, pdf 24)
25) Redo 3.1.37 using numerical integration (much easier than previously assigned 3.3.4).
A well labeled plot of v vs x is sufficient. You need not answer the various specific
questions. Of course hand in your well documented code
and explanation of your work with pictures and so on. Your code should include, in the
text comments at top, your name (highlight or circle with colored pen)
Bonus III) 3.3.4 Solution (a tidier solution is possible, full credit still available for a tidier solution)
February 21 Tuesday: Solution
February 23 Thursday: Solution
February 28 Tuesday: HW Solution
7:30-9+, PRELIM 1, OH 155 (includes through 3.5.1) Prelim Solution (updated 3/01)
March 2 Thursday: Solution
March 7 Tuesday: Solution
37) 4.1.14 (In 4.1.14 neglect the work done by the spring. Only consider the work done by friction and by the 12N
Bonus IV: Why, in Example 4.3 on pages 196-197, doesn't the `check' agree exactly with the first method? Solution.
March 9 Thursday: Solution
PRELIM 1, question 2, second chance: Do question 2 on prelim 1 PERFECTLY and your prelim score will be changed to (old score +25)/2. (As always, note academic the integrity rules, item c far above). Hand this in on a separate piece of paper (or two pages stapled), not attached to the rest of your homework.
March 14 Tuesday: Solution
45) BJ 6.98
Some Statics reading (also relevant to dynamics):
Representation of forces on Free Body Diagrams: RP pg 82 (pdf 100)
Action and reaction on Free Body Diagrams: RP 96 (pdf 114)
Logs as bearings: RP 112 (pdf 130)
Pulleys: RP 114 (pdf 132)
Wheels: RP 120-121 (pef 138-9)
Static determinacy and linear algebra: RP 142 (pdf 160)
Bonus V: A person mass m_p (m subscript p) stands still at one end of a stationary boat m_b. The boat is in a fluid that has a drag force opposite to the motion of the boat and is proportional to the boat's speed (F=Cv). The person walks a distance L from one end of the boat to the other and then stands still again. When all has come to rest, how far have the boat and person moved? a) First do the problem with C=0. b) Then with a non-zero value of C. c) In what way does the answer to (b) converge to that of (a) in the limit as C goes to zero?
March 16 Thursday: Solution
March 28 Tuesday: Solution
March 30 Thursday: Solution
April 4 Tuesday: Solution
55) 6.3.12 (Note that both times in 6.3.12 where it says “radius” it should actually say “diameter.”)
April 6 Thursday: Solution
57) RP 9.30 on book page number 803. Do this easy problme first. Do it as soon to April 6 as possible.
59) 6.4.26 (Hint: velocity of P = velocity of P, both ways you think about it.)
60) 6.4.29 (In 6.4.29 let *aO = 0. Ignore all of the text about stuck teeth and point A, its a confusing, misleading distraction. This is a simple plug and chug problem using the 5-term acceleration formula.)
April 11 Tuesday: Solution (note
academic integrity rules at the top of this page)
April 13 Thursday: Solution
[April 18 Tuesday: 7:30-9+, PRELIM 2, HO
B14 & HO 110 (comprehensive, includes through 7.1.6, prelim
2 solution) Manish prepared this list
of old prelim problems that you should be able to do in preparation for this
Moment if Inertia reading guide: Thomas and Finney 11th edition sections 15.1-6 (especially 15.2).
Ruina and Pratap 410-436, 480-499 (especially 410-419). Also see last two tables at end. ]
April 18 Tuesday: Solution
April 20 Thursday: Solution
**) On a seperate piece of paper that you hand in Thursday April 27 please answer the following questions in complete self-contained phrases or sentences. Put your name and section and TA at the top
A) Do you intend to take the early final exam?
B) Do you intend to take a makeup prelim? Which one?
C) Do you intend to take the "homework" exam?
Please hand in this sheet even if your answer is no to all questions. You must hand in this sheet if you want to take any of these exams.
68) 7.2.33 (neglect the mass of the cable)
69) 7.2.45 (Need to calculate the friction torque with an integral. If you think that friction integral is interesting, here is an essay about it and related integrals. The lead author, Suresh Goyal, was later featured on the cover of the Wall Street Journal for his work dropping and breaking cell phones.)
April 25 Tuesday: Solution
71) 7.3.22 (For 7.3.22 only evaluate for µ = 0, 0.5, 1.0)
72) Web assignment. MUST BE COMPLETE BY TUESDAY MAY 2 AT 3 AM.
"STATICS INVENTORY. "
* You must start and stop this test between Tuesday April 25 at 11 AM and Tuesday May 2 at 3 AM in a single sitting.
* You should set aside approximately one hour to take the test, although you may take more if you need it.
* Please take the test entirely on your own, without the help of other people, notes or books. Answer all the questions to the best of your ability.
* Your actual score on the test will not affect your grade. BUT, you must answer every question serisiously. And, based on much accumulated data of students taking this test, they can tell if a student did not take the test seriously. Finally, I have a bet that this class will do better than any other class at any other University ever.
* Go the web site: http://engineering-education.com/statics/
Enter the Code: CNAR06S1.
Enter your university email address (whole thing, with @cornell.edu), and your name.
Click on Submit. Choose the appropriate gender and race/ethnicity designations.
Click on Start Test.
* Note: if you did this on or before Friday 4/28 early afternoon, the automatic grader was
sending out incorrect reports of student scores back to the students. If you got an email that
says you didn't do so well, when you think you did do well, just ignore it.
April 27 Thursday: Solution
73) 7.3.25 (assume m2 does not rotate; the two springs are very close together)
75) 7.3.41 (easier than it looks, simple answer)
May 2 Tuesday: (due Tuesday May 9: can give to your TA on Thursday May 11 with no "late" charge) Solution
May 4 Thursday: (due Thursday May 11, give to your TA) Solution
May 9 Tuesday: Optional HW exam (Thurston 205), written request must be handed in in lecture on April 27.
May 15 Monday 9-11:30
Final Exam Early Makeup, (Ohlin 155)
Prior email permission from your TA needed for either of these.
May 19 Friday: Final Exam,
- 4:30 pm (Rockefeller Schwarz auditorium)
Rooms posted by March 31, 2006 at http://registrar.sas.cornell.edu/Sched/finals.htm