Welcome to the first week of discussion!

1. Welcome to the first week of discussion! • If you get here early, think about both problems!: • A “force polygon” is a closed shape (polygon) that we construct by adding force vectors geometrically using head-to-tail addition. • On the “Minimizing Forces” problem, • Try and draw a force polygon involving F1, F2, F, and the resultant R (include arrowheads on the vectors for now!). • Can you draw this polygon so that R is “minimized” (i.e. has the shortest length possible)? Hint: exploit the fact that while we know the direction of F, the magnitude (length) |F| is not specified. Adjust the length until you see a condition for |R| being of minimum length. • Think about this: • How is this polygon useful? Can we use it to find what we need? • This force polygon should be a quadrilateral (we have four vectors), but we do not know any laws to compute lengths/angles in quadrilaterals…how could we generally proceed to find what we need in this problem? • On the second problem, we need the diameter, how is this related to the separation distance r in the gravitation equation? What do we do about the masses in this equation (not known)? Itcanbeshown.com Sirajuddin, David

2. Welcome to the first week of discussion! • Hello! • As we go through the class, please feel free to interrupt me, or raise your hand with any questions/comments Itcanbeshown.com Sirajuddin, David

3. Who am I? • Name: David Sirajuddin • BSE in Nuclear Engineering from Univ. of Michigan • 3rd year PhD Student in NEEP dept. at UW-Madison • I study experimental plasma physics for nuclear fusion energy • …Like in Iron Man, not Spiderman 2 [LHD] Itcanbeshown.com Sirajuddin, David

4. Who am I? • Hometown: Portage, MI • I have been a Statics TA for two years now, so (hopefully) I know what I am talking about by now [LHD] HSX in Engineering Hall Itcanbeshown.com Sirajuddin, David

5. What we do in discussion • Discussion is an interactive session! • Feel free to interject me anytime • I am not trying to fool anyone, if you do not understand something I am doing or just do not agree with me, let me know ASAP. If I cannot answer your question on the spot, I will get back to the class later about it. • Typical discussion agenda: • Attendance • Review any sticking points on returned assignments • Review any key slides from previous lectures • Answer upcoming homework or any other questions about the material (~ 10 minutes) • Work through one or two problems together (~ 40 minutes) Itcanbeshown.com Sirajuddin, David

6. Grades • Who grades what? • Connect HW: computer graded • Design HW: TA graded • Exams: one TA grades one exam problem for every student in the class • All of us TAs have been working together now for at least a semester. We are all in communication to establish grading consistency, i.e. there is no “easy” or extra “strict” TA in a damaging way grade-wise (really). If some inconsistency is present, we will resolve it in the end. • Your final course grade will be assigned by Prof. Plesha approximate straight grading scale and weights: Itcanbeshown.com Sirajuddin, David

7. Grading Policies • Design (DSN) Homework • 2projectscombined = 10% of total grade (5% each) • We will talk about how these are graded later on in the semester, I will try to get a rubric uploaded for all students to see ASAP • For future reference: • Sample rubrics from Fall 2010: • DSN1: http://www.itcanbeshown.com/For_Students/EMA_201_DSN1_Fall_2010_Grading_sheet.pdf • DSN2: http://www.itcanbeshown.com/For_Students/EMA_201_DSN2_Fall_2010_Grading_Rubric.pdf • Technical writing overview • http://www.itcanbeshown.com/For_Students/Technical_Writing_Tips.ppt • Sample Design Report • Problem Statement: http://www.itcanbeshown.com/For_Students/dsn1overheadcamera.pdf • Report: http://www.itcanbeshown.com/For_Students/Design_of_Cabling_for_an_Overhead_Camera.pdf Itcanbeshown.com Sirajuddin, David

8. Grading Policies • Exams • 3 Midterms + Final exam = 70% of final grade • Different TAs grade your exams • For grading consistency, one TA grades one question for every student in the class  You will be subject to different grading biases and methods  For cosmetic issues, you should be fine if you follow the advice in this presentation (units, axes, etc.)  Note: it is to your benefit to be as clear as possible, if your work is not followable a TA may be forced to deduct a significant portion of the points due to not knowing what it is you were doing. • After you receive your graded exams back, solutions will be posted for your review. You should check to make sure the TAs graded your work accurately. • If you disagree with the way something was handled on a particular question grade-wise, you will have an opportunity to submit your exam to Dr. Plesha for a regrade. Please only do this if you have a reason, and know the reason. Thinking you just “deserve more points” does not make any sense to anyone. Itcanbeshown.com Sirajuddin, David

9. Grading Policies • Exam problem solution deductions (not necessarily how other Tas grade) • Routine Deductions • Units must be used every time you write down a number (this defines what that number is), two levels of deductions: • Larger deduction: Noticeable negligence of units (including when units are only in the final answer) • Smaller deduction: When units are present, but the use is inconsistent • Coordinate Axis • Deduction if a needed coordinate axis is missing (i.e. when not in the problem statement itself) • Free Body Diagrams (FBDs) • A variable amount of points are deducted based on how many needed FBDs are missing. • An FBD is not a drawing of the scenario, you need to draw the forces too. • Forgetting “= 0” (see below) • This is a statics course, so obviously almost equation you write down “= 0” but you have to write it. • Note how I labeled the equations below (“sum forces in the x-direction”), please do not just write down random equations. • I will only mark points off if a gross neglect is shown N.B. All these deductions are per problem

10. Grading Policies Itcanbeshown.com Sirajuddin, David

11. How to get help • Walk-in Help – • Fourth floor, near the vending machines. We are located in the area designated with an overhead (red) sign that reads “Engineering drop-in tutoring.” • Feel free to get help from any TA Itcanbeshown.com Sirajuddin, David

12. How to get help • Prof. Plesha office hours – MWF 10:30am – 11:30pm • ΠΤΣ Mechanical Engineering Honor Society Tutoring (Wendt Library, 4th floor): • Sunday to Thursday at 7pm – 9pm • HKN and Engineering Student Services • My “office hours” = walk-in help, but you are welcome to come to my office anytime to see if I am around (2336D Engineering Hall, http://www.itcanbeshown.com/For_Students/map.PNG) • Email me any questions: sirajudin@wisc.edu, or I can meet you outside of class for additional help (i.e. by appointment) • Discussion website: http://www.itcanbeshown.com Itcanbeshown.com Sirajuddin, David

13. How to get help from me • David Sirajuddin • Office: 2336D Engineering Hall (right down the hall) • Email: sirajuddin@wisc.edu, david.sirajuddin@gmail.com • My WIH hours: • M: 4:30pm – 5:30pm • W: 12:05pm – 1pm, 4:30pm – 5:30pm • R: 11am – 12n • F: 12n – 1pm *R means Thursday Itcanbeshown.com Sirajuddin, David

14. Discussion Website • http://www.itcanbeshown.com (under the “For Students” section) • Much of what we do (and more) in recitation is on this site • Problems and solutions (more than we cover in section) • Exam review sheets • Slideshow presentations (like this one) • The actual grading rubrics we will use to grade design projects • A sample design report • If you forget the URL, refer to any one of my emails, it is in my signature Itcanbeshown.com Sirajuddin, David

15. Questions? Itcanbeshown.com Sirajuddin, David

16. Sorry, no icebreakers • For Design projects, you *may* be allowed to work with other students • At some point, you may find yourself needing some assistance. • Your peers are an excellent source for collaborative conversations/work (just make sure you still learn) Itcanbeshown.com Sirajuddin, David