Some comments from (presumably) students and some responses.
MAE 325, fall 1999

WARNING: After this paragraph, these comments are in chronological order and are not edited. The tone is often sour. These could be the comments of just a few students. They certainly have some valid content, as do my responses. But the overall tone of attack and defense is probably not useful. This experiment, of having unedited comments and responses will probably not be repeated. This was, by the way, my first time teaching this topic. -Andy Ruina (1/25/2000)

On 8/27/99 someone wrote:
The homepage is very bland, athough it does have necessary information. Visual representation of some of the information would definately be better along with some links to course related stuff on the web. Bigger fonts would be nice too.

Ruina responds: Thanks for your prompt comments. So much do I hate WWW pages that are hard to navigate, no matter how attractive, that I tried to make this one just vanilla and functional. Visual stuff could be nice, but probably my time is better spent thinking about the course material. Links to other related pages may be added as we discover them. Small fonts were chosen so that printouts wouldn't go on for lots of pages. But we could change all of this if we had an energetic webmaster volunteer.

9/12: First of all, we should do less (perhaps none at all) of MATLAB. I have spoken to my friends who have taken this course before last fall and over the summer, and according to them they do not have to do any MATLAB crap. Just because we have an instructor who is in love with MATLAB this semester, we have to go through all these added crap. You talk about COrnell being an unfriendly place, but you don't try to make it less hostile to us. We spend a lot of time on homework. Even with the help of the TA during office hours, it takes us a few hours to do TWO problems ! This does not make any sense. We have other classes as well. Please give easier homework problems. Or otherwise, have added office hours, and make sure that the TAs know what to tell us. Make sure they know how to guide us clearly.

Ruina responds: You have a few points, let me treat them in turn.
• About Matlab. I don't love Matlab. I think it has multiple annoying defficiencies. And I am not that good at it, actually. It is just the package that I picked as most appropriate about 6 years ago when trying to promote a standard for the college. And today, still, on average I would pick it over, say, C++, Java, Fortran, Basic, Pascal, Mathematica, Maple, Macsyma, TK-solver, and MathCad as the preferred package for standardization for engineering calculations. I have promoted Matlab exclusively, though, not because it is far superior to all other choices for all purposes, but because it is more efficient for students to use one package in a variety of courses than to learn a different package for each course that uses computation. In some recent semesters of MAE 325, following the whims of the professors and texts, students have had to learn some combination of Powerpoint, HTML and TK-Solver. I am not complaining about this, but it seems no worse than using a package that is useful for many courses and is likely useful in the industrial world outside. I think you will be better off as an engineer if you have some facility with using a computer for engineering computations and my promotion of Matlab is to serve that end.

• Cornell is unfriendly. I do think that Cornell could be more friendly to faculty, students, and staff various ways. One problem, which your comment exemplifies, is that students and faculty often see the other as against them rather than as partners. This is a vicious circle which is hard to break, especially in the context of grades. I would like to think that my biggest aim is your education and that my choices, even if they make demands on you, are based on that goal. I would like to think that my use and promotion of Matlab is based on my desire to serve you, not my hostility towards you, for example. But if you have other ideas please let me know.

•Two hours to do 2 problems. I guess I don't see this one. You can only learn by thinking hard. If you can already do a problem before you do it, it doesn't have much to teach you. Thinking hard for a long time teaches you more than thinking hard for a short time. If this class required 10 hours of homework everyweek, it would still not be out of line with the overall expected learning time for someone in an a college environment that is supposed to be saturated with learning. But I don't think that it ofetn does.

•More office hours. We have had 20 office hours per week scheduled since the start of the semester. Two more will be added in a week or so. If these are at a bad time please let us know.

•TAs. I think you are right that sometimes the TAs have different opinions from each other and from me and sometimes the TAs haven't fully read my mind about my intent. We are doing our best to keep coordinated between the staff. If you notice specific weaknesses or discrepencies please let us know.


9/12: The point of this class, as all other classes is to learn. You being the way you are to students at lecture in no way adds to the learning process. Please make lecture a place where I won't to go, not a place where I want to avoid the teacher because I am afraid he is going to make fun of me.

Ruina responds: I agree completely with the first and third sentences above. Class is for learning and you should not feel put down in class. My style includes some sarcasm which can be interpretted as gentle teasing or as insulting. Over the years I have found most students take my comments lightly (they notice, for example, that I insult myself as often as I insult them). But some students, like you apparently (at least as of this writing), think I am an arrogant, insulting jerk. Since getting this email I have tried to lighten up a little. You try too, ok?

9/13: The idea of in-class prelims was mentioned but vetoed in class one day last week, primarily because of limited time in class and the idea of morning prelims. What about having prelims in lab?? This would eliminate the evening prelims yet still allow ample time for suitable problems.

Ruina responds: Its a reasonable idea but for one problem. Writing 3 prelims. This takes lots of staff time and also is prone to being, or being interpretted as, unfair between the sections.

9/13: I have noticed that your last couple of lectures have all ended late. We make an effort to get to class on time, can you please try to end on time? Thanks.

Ruina responds: Since getting this email I have tried to be more timely. Like my crusade to spread Matlab, I have been working on getting the class clock to proper time. That may help.

9/15: Just thought you should know that the last hw set (#3) was very long... I think we could have learned the same amount from 3 problems considering how long each one was.

Ruina responds: So I heard from a few sources. I made HW 4 a little easier to make up for it.

9/15: According to the final exam schedule the exam for M&AE 325 should be December 15, the very same day as the M&AE 323 final exam. Since both of these classes are required for all junior MechE majors, is there any way an earlier exam could be given? (Also, the exam for Physics 214 -- another course that many juniors are taking this semester -- is December 14.) The exact date of the final is not listed on the syllabus, so you may already be aware of this potential time conflict. I (and I'm sure many other fellow students) would appreciate if you considered changing the scheduled date for the final or possibly offering an option to take the exam at an earlier time. Thanks.

Ruina responds: The great Nanette Peterson in the MAE office is looking into this. Don't buy plane tickets that leave before the end of exams though!

9/17: Please post the solutions to problems 2 and 5 (I know you already did this in class but a hardcopy of the full solution is theONLY way I will learn) because I don't know how to do them. I repeat, I, as a student, speak unofficially for many others, when i say I know from experience that the ONLY way I will learn is if there a are neatly presented, hardcopy, detailed solutions to a number of sample problems that we get long before the HW is due, or IN THE LEAST we are provided with detailed solutions for the HW.

9/17: I regret to inform that HW 3 solutions weren't up yet, and I believe that when I said solutions to problem 2 and 5 weren't given, I was referring to HW 2 when I thought I was talking about HW 3. I think the solutions to HW 2 were very well done. Kudos to you and the TA who wrote them. I am sorry

Ruina responds: I didn't quite follow this. But I assume that all is ok. If not, please let me know. The TAs are working hard to give you good solutions as we all appreciate. But if you do find fault, please let us know.

9/27: Thank you for class today, it was wonderful! Relating the cryptic stuff we learn all of the time to the physical cool stuff that I want to know about is the way to excite and motivate... I look forward to the next lecture

Ruina responds: Thanks. If only I understood how this lecture was different from the others! Seemed the same to me, more or less, oh well. (The lecture was the first one on singularity functions.).

9/29: The problem with MATLAB is that all our classes teach us the basics, spend 10 minutes going over something like ODE23 and then expect us to know how to use it for homework problems like problem 4 from this week. I had enough trouble just trying to figure out what your code meant, never mind writing my own. If you really wanted us learn how to use MATLAB it would be better to give us some easy problems for us to work out (more than 1 or 2). What you are doing is the same as buying a kid a bike, telling him he's got to hold the handles bars and press on the pedals, and then expect him to be able to ride the bike anywhere. When he can't all you say is, "What's the problem? It's easy, all you have to do is pedal."

Ruina responds: I gave two full lectures, not 10 minutes, on how to do the required programming and gave plenty of time for questions. I will do more. Matlab solutions have been provided and examples have been put on the WWW.

9/29: I just spent the past six hours working on problem four of assignment five and as I was looking at the moment data, I believe the solve command got overloaded and crashed matlab. At the same time the two m-files I had been working on were mysteriously erased leaving me with absolutley nothing. This assignement turned into an incredible waste of time and left me frustrated and digusted at computing assignments in general.

Ruina apologizes: Sorry.

9/29: Please don't exam us on MATLAB.
10/4: I don't think that we should be tested on matlab.

Ruina responds: Its part of the class. If it weren't on the exams I think lots of people wouldn't take it seriously on the homework.

10/2: I think MAE 325 has gone from being a course in mechanical design to a course which is a combination T&AM 202 and T&AM 203 on steroids.That four bar linkage problem last week was outright ridiculous. It was more of a project than part of HW set. You say that we should be "saturated" with learning...but I believe that learning is a process which should involve more than problems involving bicycles. Aren't Ivy League students supposed to come out as Renaissance men? I'm all for acquiring useful and interesting practical knowledge which will help me once I am employed in the engineering field...but I don't think it should be at the cost of givinng up almost all of the other big parts of the experience which is the age of 18-22.

If anything has actually killed my interest in has been course such as MAE 325. if you want us to have useful computational knowledge...then maybe you should have us work with software such as PRO Engineer instead of crap like MATLAB. If you want us to do calculations then why not have us learn something more standard like Mathematica? I am sick and tired of ! ! has the most user unfriendly interface I have ever encountered, even more than a UNIX command prompt!!

After speaking to people who took this course in previous semesters and describing our HWs...their hW's were nowhere nearly as time consuming or difficult, so why sould we have to struggle through insane problems when in the end all we will have is a grade next to the words MAE 325 on our transcript, just like those who took this course before us.

To top it all of, the one part of this course which was the light of hope in terms of actually doing something interesting has also been altered to the point that its dreary....the design project. A bicycle cart???? I can't htink of anything more mundane and boring to design. Mae 225's design projects were 10 times more exciting and challenging. I didn't mind spending hours and hours in the machine shop or doing calculations EXCEL...because it was INTERESTING and I was going to build something which I was proud of (torque wrench, air motor)

It is my opinion that the department and faculty seriously need to reconsider the curriculum for MAE 325 and how that knowledge is imparted on to the student.

Ruina responds: I have addressed most of these things before, one way or another, so won't give a point-wise reply here. I am genuinely sorry that you, and at least a few others, are so discontent. I would like to talk with you (and others with similar feelings) if you could work up the courage to schedule a personal meeting. I have little direct effect on your grade, and what little I have I wouldn't spend on retribution, so you have little to risk.

10/2: You send us too many emails. If I want to read other students' anonymous comments, I will visit this webpage. Don't email me every time someone complains about something. I have to fight myself to keep from deleting automatically anything coming from you. Thanks

Ruina responds: The email before this one on 10/2 expressed discontent about (among other things) a misunderstanding of the project policy. I sent an email to the class so that person and others with a similar misunderstanding would have time to behave appropriately. And so earned this response from you. The emails and responses posted here are not for course logistics. I don't want people to have to look here. Better that you be a little bored with my emails than have people misunderstand what is going on. Just glance and, if you know what is going on, then delete. OK?

10/2: Speaking from my experience in 225 I found that students spent a majority of their time building a prototype of their air motor Their grades were largely based on their design, presentation and analysis. 325 seems to have even less focus on building a prototype as the lab/project is only worth 15% of our total grade. And within that 15%, under which of the following categories does the completed prototype fall. It doesn't seem to fit anywhere!
     Specifications (10%)
     Design sketches and justification of final design sketch (10%)
     Detailed design and verification (10%)
     More detailed design (10%)
     Report and presentation (60%)
Can you give us some guide as to how much of our time should go into building of the prototype. I don't want to waste all my time making a prototype and find myself failing other classes when it actually doesn't make any difference to my grade.
I think designing and building something is fun but I don't want to end up failing my classes because the unimportance of building the project was not made clear. Apart from the personal satisfaction, can you please explain what other motivation we have to start a challenging project as opposed to something completely trivial. People spent so much time making air motors that were an ambitious project but we didn't get any credit for it since we worked hard but the airmotor failed.

Ruina responds: This is a reasonable question. We'll discuss it and try to give you some reasonable response. But for starters, this is supposed to be a way smaller building project than the air motor. Way smaller.

10/3: I have been reading comments that have been posted by the class and I unfortuantely have to say I agree with them. So much so, that I tend to skip class. This is the first time in the 3 years I have been here that I have hated a class so much that I don't even make the effort to get up early in the morning. I disliked Tam 203 and Mae 326 because dynamics is not my forte but I actually went to class. I had to struggle with the classes but I passed. Personally,I am more interested in design. I loved 225 because it had no exams and everything was really hands on. Whatever we had been taught up until then had to be put into practice. I LOVED THAT. I was looking forward to this class becuse i thought I'd be making those carts that are outside the design studio. It might not be practical but it's FUN! And I can't believe that buliding and designing one of those does not require the same amount of skill as would building a dumb bicycle part. I guess what we are all trying to say is if it's not too late to change structure of the course. Even if you change the hmwk it would be a great help. Look at all the complaints you are getting regarding the hmwks. We are undergrads.We are not grad students! I had a tutor (PhD candidate) help me the other time and he was surprised that I had to do those types of hmwks. You say "Thinking hard for a long time teaches you more than thinking hard for a short time"...sorry but we don't have the luxury of time. Most of us have 3 other classes,and some, like myself, have 4 other classes that we need to get good grades on.Bottom line is, please change your attitude with regards to the hmwks and the class. We are 20-21 year old engineers. we want to learn what there is to learn... for our appropriate level .. but we also want to have SOME time to relax and have fun. Sorry, but thinking of bicycle parts is not my idea of fun.

Ruina responds: A gizmo design class would be more fun for lots of students. Maybe it would even be more useful to the class as a whole, hands-on experience helps build intuition. But it is not this class. People who like to build, as opposed to plugging in formulas, are not well rewarded in much of Cornell. And this class is, rightly or wrongly, part of that trend. I worked for a year with a brilliant mechanical designer who was also basically a C- student who barely got through college. I had immense respect for him and learned much from him. Even without alot of formulas, I think he also learned things from me. I would like to think that I am teaching in such a way that, similarly, your intuition for building would be increased. Although the homework is often technically involved, there are often morals that I would hope you extract. Things that transcend the formulas and are useful for design.But I think you would have to come to class and be alert, attentive, and not hostile to appreciate this.

It is hard to gauge how long it will take students to do homework ahead of time, and I have misjudged a few times this semester so far. But you should budget your time. Even if you are interested in being saturated in learning, it is not always best to do exactly the homework and no more and no less. If you do not find the homework rewarding and educational then you shouldn't do it. Also, if you are too busy studying to think, you are, in my humble opinion, misusing your time. You are here for an education first, grades shouldn't make you a miserable slave. And anyway, you will get better grades if you grind less and think more.

If thinking about bicycle parts, or something equivalent, isn't your idea of fun then why are you in mechanical engineering? Isn't trying to understand some mechanical thing or another at least as much fun as most movies?

Here is an honest question, I would really like to know the answer. You wrote about MAE225 " Whatever we had been taught up until then had to be put into practice." How much of what you learned previously did you actually use in your design? If it was alot, how are we to teach you more such things (still below graduate level)?

10/3: Could you please have a TA give a formal review session (Someone who can actually understand us and go down to our level and not someone who teaches like we are all grad students?) And can you please give out a practice exam?

Ruina responds: The TAs are available to answer any and all questions in their scheduled office hours. The homework problems are good practice exam problems, as are the examples from lecture and section. If you can do them all on your own, and explain the steps (why they were used, what other options would work, what options would not work), you will do well on the exam. Guaranteed.

10/5: This anonymous comment page is great. It is interesting to hear how some people feel about the class and to have a professor acutally respond to their concerns. It might not change my daily life, but at least it feels like there is a place where student opinions on course content are weighed.

Ruina responds: I do use the input to try to adjust my teaching, not necessarily by yielding to the complaints, however. But I wonder if giving this forum for (mostly) negative comments relieves negative pressure or encourages negative feelings.

10/7: I'm with that 10/5 guy.

Ruina responds: It is possible to get the sense, from some of the aggressive tone, that it is all men that are posting. But I doubt that this is so.

10/6: I have read all of the comments people have posted and listened to complaints in lecture and I think it is time for MAE 325 students to grow up. People will always complain about workload and homework. No one ever said being a junior at a top Engineering School would be easy. Everyone in this class could choose to glide through engineering at any of a number of schools but be arenít. There is a reason we are studying at one the best Universities in the world. We are here to work hard, maybe harder then we have ever worked before or again. We will never know what we are capable of if no one pushes us.

10/7: I would really like it if you would post the homework. I don't want to be working on it this vacation. thanks.

Ruina responds: We'll try to get it out by Thursday late, or Friday early.

10/7: I am one of the few students who actually WANTS to learn MATLAB. I have seen it used in real engineering firms and I know its power. But, here is my point... To take an ancient chinese proverb..."I hear and I forget, I see and I understand, I DO AND I LEARN." Yes, you have covered matlab in class (and I forgot) Yes there have been HW problems that use MATLAB, but these have mainly been far too difficult for me to do and so I am forced to just study the HW solutions. Now I feel that I somewhat understand what has been done, but not nearly well enough to do it on my own. If we could have some really simple MATLAB problems that slowly built up to what you want us to know it would be very helpfull. Thankyou.

Ruina responds: First, I am sure that you are not a minority. What sincere engineering student would not be thrilled with themselves if they could honestly claim high computer skills that were useful for engineering. They whine because they are frustrated not because they would not be happy to know more. They whine because they don't realize that Matlab is basically as useful or more than other computer tools that they also don't know. At any rate, I had hoped to cover some of your points by the very first assignment this semester. Do all the Pratap Tutorials and make sure you can do ALL the problems therin. If so, then there are no big leaps. There are more things to keep track of, but none of them is essentially new or difficult. You should "do and learn". I would hope that you would use Matlab for lots of little things in this and other courses, not just for big initimidating assignments. But, following your suggestion, we are going to give a problem somewhat like the biker's leg problem, but broken into smaller pieces over a few weeks. Next year maybe we will bite the bullet, realize that some people have been disengaged when dealing with Matlab in previous courses, and build up the skills one bit at a time, from the start of the semester.

10/15: [quoting the prelim grading guide:] "The correct answer is worth 5 points. Finding the correct geometric relation is worth 8 points. Knowing how to use the two-force component principle - 7 points."        I didn't use the two-force component principle, but didn't use a wrong method, and got the wrong answer. as a result, i lost all 20 points. thats a good scam. this grading method was planned so things like this woulod happen right? i will come talk to you about this.

I don't have a problem with such extreme grading if every student's exam was taken off EQUALLY. but that rarely happens in your classes. three things that bother me: i feel i only know about 50 percent of what i am supposed to know when i really know more, that the class knows only 50 percent of what we're supposed to know(because the mean was about 58), and that knowing 50 percent of the syllabus was, what!! average and not below average!!?

I would be much happier to try harder next time if the mean was like in the seenties or eighties-- i might fight for the extra point to get me over the standard D, but I am doing it anyway, but for 20 points instead. i think the grading methods alone make the prelim unfair test of what we know. sorry if i am not being too clear.

10/15: I am obviously not a statistics major, but I do know one thing: you dramatically skew your results by adding "5 bonus points" to those who got both parts of the test questions correct. I have an idea, why not also SUBTRACT 5 points from those that MISS both parts! Consider two students taking a two question test in which each question consists of parts a and b. If the first student gets only parts 1a and 2a correct while the second student gets only 1a and 1b correct, there is no reason why they should get different grades. The "bonus" should be added after the mean is calculated, otherwise "the rich get richer and the poor get poorer."

Ruina responds: Let me respond to these two comments in parts:
1) A mean of 58 or 38 or 78 is not good or bad. These are numbers not statements on net worth to God or society. No one in this class knows a quarter of what they could know about the subject and all know 300% more than typical people who are not studying engineering. A perfectly good exam could have a mean of 10%. In one exam I took in college I got 12 out of 120, and that put me in the top third. It meant I got one out of 10 problems right, about which I was thrilled. Another perfectly good exam could have a mean of 95%. If you like, just add n points to your grade and that of everyone else in the class. Such would have no effect on anything. But if it makes you happy I don't mind if you tell your Ma that after rescaling by addition of n you got 50 + n. What makes an exam good or bad is that the work shows what the students know and don't know. What makes it fair is if the range of scores is mostly a reflection of knowledge and not of flukes in the grading or random minor carelessness of the test takers. But whether this range is or is not centerred at 75 with a standard deviation of 10 is of no consequence (but to students who have the misconception that the numbers have meaning).
2) The grading guides, such as the one quoted in the first of the two comments above, are to show students the philosophy of the grading and to keep it consistant. Exceptions are always made for students whose work does not fit in the scheme as laid out. Certainly someone could get high marks without using two-force members, for example. After learning at least one way to do the problem correctly, come talk to me about it and lets see if you were graded a way that I think is fair. Best would be if you learn to follow your own approach to completion so you can show how it goes or see for yourself that it doesn't.
3) I think there is a substantial difference between getting 1a and 1b right than getting 1a and 2a right. The bonus for doing both parts was meant to be in the spirit of:" Do a or b, whichever one you like better. If you are really acing things and have time, do both parts." Also, for those problems, once you have the answer to (a) or (b) the other one follows almost trivially.

4) When bonuses are added is of no consequence. This course, LIKE ALL COURSES AT CORNELL, is graded on a curve. Teachers who tell you otherwise are decieving you, themselves, or are of an extremely rare bread that I have never seen. The curving comes either as
       a) literal curving with the final grade distribution and giving so many A's, B's, and C's, or
       b) adjusting the harshness of the exam and fianl project grading, or
       c)  adjusting the difficulty of the exams, or
       d)  adjusting the overall difficulty of the course from year to year.
If you think you know of a teacher that does not grade on a curve imagine the following. In a given year the teacher gives the average student a B-. Over a period of three years the students coming into the class change, on average to be like the students in the top half of the class or the bottom half of the class. Do you think that from that point onwards the course grade averages would be correspondingly changed? Or, instead, would the teacher adjuct her grading scheme to keep the average student near a B- grade or so? If the latter, which I think is the case, this adjustment is a form of "grading on a curve". Typically it happens within a semester, not just between semesters.
Once you accept that things are somehow curved, it makes little difference what is the mean on a test, when bonuses are added, whether you get to drop the lowest grade, etc. These are only "feel good" actions that have little net consequence.

Given all of the above, I would rather have students happy than unhappy, even if their unhappiness has no base. So we'll add 12 points to all students prelim 1 grades. It does no good, but no harm either.

10/16: Could you please put the book on reserve in carpenter so I don't have to lug it around? (God forbid I grow some muscles). Thank you.

Ruina responds: I have asked for 3 copies to be on researve by noon Monday October 17.

10/18: Hypothetical situation: 20-25 points were taken off students who had a slight mishap in problem 1 (the reasonable penalty whould be about -8 points). They had problem 2 and 3 done correctly. Other students lose 10 points on either problems 2 or 3, but get problem 1 correct. Let's assume that the 3 problems were equal in difficulty level and that the mistakes made all students were either _equal_ or greater by those who made errors on problems 2 or 3. The result: the wrong students end up in the bottom third of the class0-- typically, those who messed up to the sligthest on problem 1. Hypothetical situation? no longer. not after Prelim 1. What did these students learn? nothing. gain? anger. there is no good justification for how problem 1 was graded.

Ruina responds: You write as if you think there was a fundamentally unfair misguided conspiracy in the way problem 1 of prelim 1 was graded. It is totally possible that your test was not graded reasonably, even without an evil conspiracy. If you did good work that didn't happen to be of the type specifically listed but was of equal use towards the goal of a final solution then you should get substantial partial credit. If this is the case you should work out the problem to completion on your own (don't write on the test) and show this to, say, me or other 325 staff and submit your test for regrading.

10/25: Greetings from an English teacher/school administrator. I was recommended this page/site by a former student and current Cornell mech. eng student and find it COOL! Prof. Ruina is to be commended for his passion for his subject and the willingness to hear criticisms! Remember "A student who is not asked to do the impossible, never does all that he can do." (John Stuart Mill)

Ruina responds: "or she". Thanks. My sister, also a teacher, also thinks its cool. She wants a similar page so her kids and friends can whine anonymously to her about brocoli for dinner, not enough phone calls and such like.

10/26: If you're going to assign a homework problem with multiple parts that extend from week to week, i think it's only proper if you return each part to us graded before the next part is due. it may be true that we can look at the matlab solution on the web, but like you said in class, looking at matlab and actually writing the code ourselves are two very different things. it's much better if we can see our own code to see what's wrong and what's right in our way of thinking/programming. can you please have the next part of this fan problem graded and returned to us by the time the third part is due? thank you.

Ruina responds: One of the nice things about computers is that it is so easy to save your work. Of course you should be able to look at your old MATLAB code when you do later homeworks. But just like anything else you write on the computer, you should save your matlab code when you write it. Are you sure that you don't have it somewhere? You can tell if it is right or wrong by comparing with the posted solutions. As far as pinpointing your errors goes, that is a debugging problem that is too detailed to expect that the grader will have helped you much. In summary, sorry, I don't think we can speed up the grading that much. But I don't think that should be slowing you down either.

10/31: I understand your response to the 10/26 comment, the solutions are on the web. However, I don't think I am alone in saying that the Matlab code on the Web is far more complicated than anything that we write. In addition, it's hard to follow something that has completely different variables from our own code when trying to figure out where we went wrong, if we did. I agree with the 10/26 commentor that it was really hard to do the second part without a corrected part without a corrected version of the first part with our own variables in hand. I am hoping that this is not the case this coming week with the third part of the Matlab problem due.

Ruina responds: I guess one thing which wasn't clear in the assignment statements is this: part of your assignment each week is to get your code from the previous week fully functional. By breaking the assignment up in to pieces we did not mean to give a reprieve for all past errors. Would that the graders could look at your code and debug it and you could move on from there. The grader can look at the quality and applicability of your drawings, the layout of your code and its documentation, the niceness of the layout of the output and the plots, and the correctness of the output. Hopefully the grading will guide you in how to better organize and present your work in the future. But not in finding the details of your errors in the finite amount of grading time available. So bring your old code and copies of your drawings to office hours and sit down with a TA and see if they can help give you debugging hints.

One hint: graphs often are a big help in debugging codes that have to do with physical problems. You can often find programming errors by making graphs and seeing how they do and do not make sense.

11/4: I like your class a lot. you are a nice professor. i love matlab and think you are cute:)

Ruina responds: A nice note, even if we don't know who "you" is (but I agree that Professor Valero-Cuevas is nice and cute). Also, with our lax security on this WWW page, we can't know that you aren't just a kind soul outside the class. But cute and nice anyway.

11/5: How come the lab TAs don't really do anything during the whole lab? They just hand us out a problem, see if we do it correctly, don't help us to do it, and hand back homework. They don't help at all with the project either. We were never told stuff like where to purchase items, how to purchase items, were and how to test parts,etc. They just said, here, do this project, and sat back and watched. I'm not sure, but I don't think that's how TAs are supposed to operate, or is that their actual job description?

Ruina responds: Ruina responds: The TAs are supposed to be actively involved in working with students for the full 2 hour lab meetings (less occassional gaps for student thought). All of the TAs are new to teaching and need lots of feedback about how to better please you in this time. My sense is that they are all sincere hard working people who would change their behaviours to please you if they knew what to do better. You are in the best position to give the TAs the feedback they need to please you more. You could also explain the situation in some more detail to me or Professor Valero-Cuevas or via this anonymous WWW forum (put "private, not for posting" in the contents if you like).

11/7: Hey Professor(s) Ruina and seem to be getting a lot of flak about this class lately. Now, I'm not saying I find it particularly enjoyable...I find it to be a lot of review (which could be good or bad, I guess), but I think some of the criticism is a little harsh and unnecessary, so I thought I'd send a note your way. Personally, I think the MATLAB is actually a decent thing for us to learn..perhaps not overkill style with that initial crazy four bar linkage, but in general. The problem sets have been okay...some harsher than others..but also some relatively real complaints there. I guess my main problem at this point is really finding a point to the course in general. I feel like it doesn't have direction. We're doing design and analysis...kind of...but we did that more intensely in, what exactly is our objective? I have major problems with taking a course for which I see no particular use. Okay, that sounds harsh..but, I'm just saying.

Ruina responds: The course is defined by the big red book (quoted on the course WWW page), oral tradition, and the textbooks available which have co-evolved over the years with similar courses around the country. But for starters you could say the course is about what the book is about, but less because there is too much to cover in one semester. So the course is about those things that fit within the book, the course catalogue, and those things that we, the Professors, are important for you to know, even if this involves review.

11/12: This homework is absurdly hard. And by the way, your dynamics book sucks, that's why it never go published.

Ruina responds: Let me respond to these points in turn. 1) Sorry. 2) As teachers say to students who are having trouble articulating their feelings, "use your words." Why don't you like the book? Send me anonymous email or let me take you out to lunch to discuss it and you can help make the book better. By the way, the book hasn't been published because it is not yet complete, terrible or not.

11/12: I think that having a project assignment, a problem set, AND a prelim all in one week is going over the estimated "10 hour work limit" as previously stated. Plus, there is another problem set due the day before Thanksgiving break and final cart design reports and presentations are due immediately after Thanksgiving. Is it necessary to have problem set due the week of the prelim?? And if you really think it necessary, can we at least not have homework due right before the break? I mean, we already have the huge project report and presentation to work on (and some of us would like to spend some time with our families over the "break"...)

Ruina responds: Because of this and other emails we changed the due dates a bit. But in any case, you do have to manage your time.

11/15: I feel a little disappointed with the treatment of fatigue we have done in this class so far. Although the explanation in lecture of the seemingly endless quantity of empirically derived correction factors was much more helpful than the text, it was not helpful enough to get me started on this last problem set. More importantly I cannot imagine anyone using any of these formulas in practice. "Design" classes in m&ae tend to miss the point that you cannot recreate the organic process of designing a machine which relies most heavily on knowledge gained through experience. Since the end of Ruina's 202/203 review our problem sets have consisted of lots of experience in regurgitating formulas mined out of the book. Unfortunately I don't have a solution to this problem as the m&ae faculty appear content to convince themselves that we are learning in these classes. Please don't view this comment as an attack, but as an attempt to open a dialogue on a festering and complicated subject.

Ruina responds: The later part of this course has alot to do with empirical formulae and graphs. It cannot be understood in the basic ways that the earlier, more important, topics can be understood. But things do break in fatigue, and as an engineer you have to have a sense of how to prevent this. It is as painful these experience based tidbits as it is to learn them, I assure you! As best you can, you should try to get the ideas and not stuff down nausiating facts that don't stay down long. As far as classes vs experience goes, what we do here at Cornell is the class part of education. The experience part is much harder to fit into our non-apprentice-style curriculum. I am sympathetic to the whole of your comment.

11/17: It seems that a lot of students (including myself) are very frustrated with this class. I think the problem sets are a lot of looking up formulas and making assumptions that often are arbitrary. As one example, on the spring deflection problem set we just assumed a C value? This didn't mean anything to me since I have no idea how a C=8 differs from a C=9 physically. At the very least, these ambiguous design problems clouds the overall ideas we are trying to learn rather than clarify them. I understand that when these decisions are actually made in industry there is frequently missing information but assuredly engineers have both more experience with these problems and a better background concerning the factors that influence the calculation This web page could be a useful tool for feedback to you and Prof Valero-Cuevas, however, nearly every comment that is posted is dissected and refuted. I understand that not everyone has something constructive to add but if our comments are going to be rejected every time what is the point of this page? You may not agree with me but I don't think the majority of people are submitting comments just for the sake of complaining. You said yourself that there has been ambiguity in course material and class administration over that past several [years] this class has been taught. I think it would be usful to address these issues based on the feedback of the class that has been so freely given rather than pushing them aside to arise next year. If you disagree with any specifics in this comment please address the spirit of the feedback rather than point by point refute everything I have said. Thanks.

Ruina responds: Sorry if I seem defensive. I have tried to show where I am sympathetic to comments above. Also, several things about the course DID change in response to these comments. I agree that the empirical parts of the recent material are frustrating and seem to lack a conceptual framework. Some take-home messages, hopefully, are that when you do go to design things you will be aware that cyclic loads are different than static loads and that even some predictions of failure don't just depend on stress but on the size of the piece, that C=9 thing, or whatever it was. (Why is the latter true? I guess we should do better about explaining such things to the extent that we understand them.) But one sign that I agree with you is that I pushed the 202,203 thing as much as I could (and still fit in the text and syllabus) because it is important for design AND is conceptual and thus can have a long term impact on your way of thinking about things. In the best of all possible worlds we, the teachers, would be all-knowing and could show you how all of these topics are really a form of common sense. But, unfortunately, we do not have that great perspective on these topics and have not found a book author who does either. Again, sorry about my "rejecting" tone. More thoughtful comments here and less whining would be nice. Just thumbs up and thumbs down is ok, but less useful feedback than one might hope for.


Ruina precedes: The following comment is in response to an in-person conversation.

1. I said that I thought many cornell students would rather grind mindlessly for six hours than be hopelessly lost for three hours and then work hard for one hour.

2. I asked why some people in the class seemed so hostile?

Student comment:

I've been thinking about what you said and asked last monday, or was it wednesday? Either way, here's what I've been thinking.

First you said that Cornell students would prefer to work really hard for 6 hours than to be lost for 3 and then finish the problem in 1. My thoughts included two main points.

1-How do you define hard work. It seems to me that you are defining it$ is just a very long and complicated problem. (I'm not sure that this is what you think, I am just trying to imagine) I think that most of the students would consider this to be tedious work not hard work. Students consider hard work to be work that we do not know how to do but rather are getting continually lost. We would prefer to spend 6 hours getting lost for 20-40 minutes and then making equal time of headway and then getting lost again. This way we feel that we are accomplishing something for our efforts rather than just being more confused.

2-Where does the hostility come from? I think that it is strongly related to the fact that people are so confused for so long before they begin to understand. People expect that if they go to class and pay attention and then skim the book that they will be able to do all the problem sets. However this has not been the case. It has seemed that office hours are more important than lectures in being able to complete problem sets. This is quite frustrating because lecture seems to be unhelpfull. Naturally when they find the lecture so unhelpful their anger heads straight to the person who teaches the lecture.

So the summary is: 1-People are frustrated by being lost for so long on the homeworks. 2-People begin to see lectures as useless. 3-People become angry at the lecturer.

Likely solution to problem: I don't know, if I did then I would offer to start teaching the class. However, it seems that redesigning the homeworks would be a good start. For example redesigning the 4 bar linkage problem to fit over 4 weeks was better than doing it all at once. Also try to make the lectures cover all parts of a topic. The best way to do this is to do full length examples in class starting with what assumptions to make and continueing through the equation use to the answer. Lastly choose HW problems that are easier to make the starting assumptions for and easier to see how things apply.

I hope all this is helpfull in improving the course. -student trying to be helpfull

Ruina responds: Thanks for your comments. I can't disagree with your assessment of what students want. We are not trying to give lectures that have nothing to do with the homework. In fact, I don't think we are. But if students think thats the case than there is a problem somewhere.

11/23: An add on to my comment (From 11/18) is that lectures are related to homworks, and are usefull in doing homworks. It's just that lectures are not sufficient, and not even near to sufficient for the homeworks. Most students believe that attendance and paying attention in lecture should be sufficient to complete or nearly complete the HW. However, this has not been the case. TO date the lectures have been usefull in understanding what the homework is covering, but not nearly sufficient to complete the homeworks. I suspect this is what is frustrating students.

Ruina responds: I see.

11/23: Every class has long and challenging problem sets. It's not so often, however, that students are given the chance to anonymously complain about them. My guess is that you would find an equal amount of complaints about other classes if there were more web sights like this one.

Ruina responds: Maybe. I wish there were. I think the results of course evaluatons should be public to all also. (You can see my last spring evaluations in math 294 at Go to the faculty evaluation page, pick math 294 and don't select a professor or TA, then pick stats or comments. The stats for some other courses, some, like 203 in 96 I also taught, are also available there.)

11/27: Can we use this page to vent about Fluids?

Ruina responds: Sure, I'll forward your comments until I hear a complaint from the other end.

11/29: Was anything ever done about possibly changing the date or having a make-up for the final exam?

Ruina responds: Lots was done. But it boiled down to Physics offering a makeup, which students didn't take advantage of, and OR offering a makeup. MAE325 stayed put with no need for a makeup as determined by the response to various emails to the class on the topic.

12/4: My friend and I think that 325 was a very usefull class . We used the concepts we learned in 202, 203, and 212 to do design and analysis. Engineering is about solving real world problems and 325 gave a taste of how to do that. Even though the problem sets were long and sometimes tedious we got a glimpse of what real Meche's do. As all of us know, engineering problems are not always clear cut and to the point. Professors Ruina and Valero - Cuevas did a good job of teaching and should be commended for the work they did this semester. 325 is a difficult class with a lot of material to cover and our professors did a good job at organizing the curicculum.

As a personal opinion, there are some things we did not like about the course. The Matlab was not at the level that many are capable of doing. If we had more time to become familar with Matlab, the problem sets would have been more manageable and we would have appreciated doing those long assignments even more. (Many students found the computer assignments difficult because in previous courses Matlab was rarely stressed.) As for the exams, we feel as though since they tried to focus in on how well we understood the fundamentals, then it was really not totally necessary making us do elaborate calculations for homework assignments. Giving home work problems that were concept based (without numbers) probably would have helped us reinforce the material even more and probably would have better prepared us for exams etc. or at least helped us to see the bigger picture and prevent us from doing whatever it was necessary to get the right answer, (cause the TAs told us when our answers were wrong.)

Also, doing the cart project was ok. But we felt we already had so much other work to do for the class that either the project should have counted more or we shouldn't have had so many assignments to keep on handing in. Perhaps next time, the class could be split into 2 parts: the first, a thorough review of 202, 203 and 212 through problem sets and 2 prelims, the second part, we work on our design project. During this period, we would still be learning the latter topics of the course such as fatigue, springs etc.(Actually, almost every one did some sort of fatigue analysis on their carts.) Then the final, still cumulative however, would more concentrate on this newer material.

Generally, the class was fair, and we feel better prepared to attack real every day problems. We may not be able to do an elaborate analysis off hand, but at least we understand the important concepts that go into design. We are also sorry that the students gave you such mean feedback on this page. A lot of it was unfair. We at least hope you find our input insightful and useful.

Ruina responds: Thanks for the positive feedback and the good idea about how to organize the class:

*first half engineering theoretical basics,

*second half nitty gritty empirical stuff and project.

To this day, by the way, I am actively working to get Matlab more integrated into the earlier engineering courses. Particularly CS100. There is a good chance that, starting next year, the first half of CS100 will be in Matlab.

12/4: I was just wondering if the grade statistics for Prelim 2 will ever be put up just so we could know how we are doing relative to the entire class?

Nathan responds: Meant to do that ages ago, but managed to misplace the file listing the grades. Have to get them again from the other section TAs. But will make every effort to have them up by 12/7.

12/5: We are a few students who are in the friday section. We had noticed during the last presentation that you had fallen asleep. We knew that you were fast alseep when you didn't wake at the mention of matlab on multiple occasions. We thought that this was rather amusing and no longer [feel] guilty about either sleeping in and missing lecture or falling sleeping in lecture. In addition, most of the people in the section were aware of your little beauty nap.

Ruina responds: My apologies to the students who were speaking at the friday section when I visited and dozed off. It was hot and dark and the end of a long week and ... well ... I fall asleep in almost every seminar I go to. I slept in many of my classes in high school and college too. I have a sleepy constitution. Sorry.

I am sympathetic to people who sleep in class. I usually just tease them and ask if they want to be left quietly or be waken. As far as sleeping in for 9 AM classes goes, I am also sympathetic. After my freshman year in college I realized it was pointless to sign up for anything before 10, boring, pedantic, loaded with computer stuff I thought was useless, etc, or not.

About your relieved guilt, I wish your naps in my lectures were as useful to me as my nap in section was to you. I snooze in one section I visit and you suddenly stop feeling guilty about your morning sleep, great! Would that I noticed you missing from lecture one day, or sleeping in the back row, and suddenly stopped feeling guilty about something I shouldn't feel guilty about. No such luck.

I guess that my visit to dreamland was not sufficient to generate the derogatory tone of your last sentence above. I even guess its more than a dislike of Matlab, a few long homework assignments, and a project that didn't involve alot of hands-on time. I'll buy you lunch if you'll spend half an hour trying to put words to your feelings.

12/5: Is there still going to be a final homework assignment (for the material covered in last three or so lectures)?? There is not one posted on the web as of yet. If not, could you recommend problems from our book that we could review for the final?

Ruina responds: Sorry to be so slow. But problems have been posted today (12/6). Hopefully we can get some solutions posted too.

12/10: Can you put the link to the course evaluation page on the mae 325 page? i deleted the email, and forgot to write the address down. thanks

Ruina responds:

Nathan responds: Done.

12/10: I understand that Prof Ruina may be feeling attacked because of many of the comments that have been sent, but what do you expect when you allow posting of anoymous comments?! Prof Ruina's responses to many comments have been similarly disrespectful. That's why I never wrote in to this page because it seemed that he doesn't really pay attention to most of the comments anyway. It seems like this class had a lot of potential but somehow along the way, we got lost. I think if the class had been better organized and more structured, it would have helped. For one thing, what was this class really supposed to teach us. At the end of it all, it seems to me, that 325 was mostly a rehash of 202, 203 and 212. And the last 2 weeks or so consisted of seemingly random lectures about various design parts. The course book says machine design... is that what we've been doing? Was there ever a syllabus for this class?

There is a lot of frustration among students. Why? Prof Ruina is a good lecturer but he really has to learn something about interacting with students. It might seem like we have been whining a lot, maybe that is what is sounds like. But, I think the complaining is quite valid. This class is probably the heaviest one I've ever had at Cornell. And the worst part is that rather than figure out a way to improve it, Prof Ruina seems to want to buy lunch for anyone who sends an anoymous comment and intimidate them into seeing that his way is best.

Ruina responds: I have paid attention to these comments and we have changed some things about the course in response to them. The course is largely a rehash of 202,203, and 212 as stated clearly in the first few lectures. See also the introductory pages of the text. The syllabus on the WWW was followed, more or less. I would gladly buy lunch to better understand the nature of the apparant hostility. On the other hand if you pay for lunch I will try to tell you my thoughts, intimidating or not, about the topic of your choice.

12/10: Just a word of advice (and perhaps a source of our class negativity)- ORGANIZATION is a good thing, and very important to any class. It's hard to be in a class and plan to do things when everything is very unorganized...some weeks the homework took 1 hour to do, and others took well over 10. Somewhere the homework included MATLAB, and only had 1 or 2 lectures to "help" on the topic.

Most teachers write a Syllabus before the class starts. Most have a layout of the questions so that students can work ahead, or at least know what to expect. This is not necessary, but it seems that your (Ruina's) lectures were as unorganized as the whole course was. This made class hard to follow, hard to understand, and keep up with work in general.

A little organization would have gone a long way. Perhaps maybe you (Ruina) wouldn't have been as lost during the lecture before Thanksgiving Break if you had been a tad bit more organized (as it seems that you were embarrassed by this).

As far as this class goes, I think having a clear goal for us would have been a nice thing. I am not sure what we were building up to, was it the design project? How come you didn't see all the design presenations, not just the Friday lab? Were you interested in our designs at all? Once again, the whole design process was frustrating because we didn't know exactly what was expected of us.

I, personally, got a lot of out of the project. Stuff that I consider more valuable than the homework, or even being able to get a 100 on a prelim. This "stuff" is what I took 325 for, and I think most everyone would agree that this was the most valuable "stuff" in the course.

Good luck teaching this and anything else in the future. Just a reminder: COURSE ORGANIZATION!!!

Ruina responds: I agree that a course with a strict syllabus and with all the homework assigned on day one is easier to live with, for both students and faculty. I was not familiar enough with this course to do this this time, however. Also, having an even homework load is easier for all. This we also failed to do because of lack of experience.

Lack of organization is not to blame for my lack of preparation just before thanksgiving. The topic of my bad lecture was pretty much as scheduled. Actually with less organization I could have just picked a topic that I knew well enough to lecture about and given a good lecture.

The design project was intended to include a synthesis of some, but not all of the material. I thought about cancelling the design project from the course (the text's author so suggested) but left it in because I know some students like projects.

I didn't think it was a productive use of my time to watch 9 hours of project presentations. Maybe that was a bad judgement, I don't know.

12/10: Falling asleep in class is WAY different from falling asleep during a presentation that YOU assigned. We PAY to be here...if we want to waste our money falling asleep in class, that's OUR choice. You are PAID to work here... if you want to fall asleep during something you asigned us to do, YOU are wasting our money, that's not OUR choice.

Your reply to the email sent to the student who originally wrote that email was 100% unacceptable. Perhaps the student should have asked a person sitting close to you to poke you and ask you if you wanted to be asleep. Would that have been acceptable?

Ruina responds: It would have not just been acceptible, but nice, if someone had given me a nudge and asked if I wanted to be asleep.

12/10: this is my first time writing and i have a lot to say about my disappointment in this class...

my first thing is that i don't have a clear idea about what this class was supposed to be about, including from the vague description that you have been giving out since the beginning of class - i believe that a lot of flak that has been given out by the students is that we don't see or understand how this class means much in the long run - all this class has been is a 202 and 203 review and not even thorough at that - and then it has been a piecemeal, quick overview of what i think that this class should have been about - MACHINE DESIGN

i agree with an earlier comment that the problem sets could have emphasized more concepts instead of numbers

i also believe that instead of a lot of problem sets, the class could have been more organized in letting us get a feel for design - ie. specific case studies are introduced in class, and the students work on them in groups during lab and turn in their analyses instead of problem sets - that way - a lot of engineering design can be incorporated into one class. also, this would have been a perfect way to integrate real world computer applications such as ProE and Matlab.

for example, lab time could have been used better by allowing us to say, improve on a previous design by possibly buying the product, benchmarking and designing a new product, presentation and all; that way we could have been more prepared for a final project that could have been worth more

lastly, i would like to make a comment on your failed lecture on screws and your lack of respect for others when you slept through friday's presentations. there are many excuses that you can give for not being prepared for class and for sleeping through lab, however, they are just that, excuses... for those of us who showed up on that day, you should not have made two problem sets due and then not expect that a reasonable percentage of the class would show up and for falling asleep - listen, you assigned the project, only show up for one lab section and then fall asleep? i think that that is one of the most universal signs of disrespect - if professors don't have to put up with it, then why should students? we pay to be here, you are paid by us to be here

anyways, that's what i have got to say on the topic

ps - if you were to fill out an evaluation for yourself - do you believe that the course was coherent, it accomplished what is was supposed to (were your expectations met) and that you feel that you did a good job of teaching us?

and i am not writing this to be mean, or rude, but...feel free NOT to comment/ dissect everything that was mentioned in this comment - but let it serve as some sort of constructive criticism for future classes that have may have some vague description that you don't know how to organize...

Ruina responds: I agree that the goals of this class were not, and are not, clear enough. For the class to be about "Machine Design" would that mean spending a bigger fraction of the course on the later parts of the present "machine design" text book?

That I DO put up with sleeping in class and that I DO fall asleep in most lectures I attend, and that I myself don't have a double standard (even if us professors as a group seem to) is not an excuse for my rudely dozing off.

If I were to evaluate the course I'd have to do it 2 ways. First pretending that there was no hostile student feedback. Then I'd say the course was OK. I have trouble understanding its place in the curriculum, as do I 212 and 225. Thus the course went OK, as far as reinforcing 202,203 and 212 concepts and introducing some of the issues of design. But it does lack focus (as does the text used, in my opinion). The second approach is to look at the student feedback. I have never before dealt with such negative feedback. Perhaps when the evaluations come in I will see that it comes from a small number of people and perhaps not. In any case I would say the course is a failure, no matter what it covers, if it turns people so negative. Although I can list a bunch of features that people complained about, I don't guess that they explain the negativity. Certainly if I teach the class again I will try to have a preset syllabus, pre-asssigned homework, a more gradual introduction of Matlab, more clear statement that the course involves review, more even homework assignments and I would try not to fall asleep in public. But I think there is more to it than that which I still don't grasp. Thats why I'd like to talk in person to a few of the really negative people.

12/12: where is the test?

Ruina responds: Kimball B11

Nathan responds: The correct time and location are now listed on the syllabus. For a while, the information on the syllabus was incorrect.

12/15: The final exam you gave our class this morning is the quintessential example of your inconsistencies in teaching and testing important concepts as well as your lack of establishing fair expectations for your students. Did you set out trying to get us and trick us? Having an exam where the mean is a 75 does what harm? While working on it, we can feel confident and calm rather than getting frustrated and annoyed at the exam, which thus detracts from our ability to think clearly. The latter was the case with your exam this morning. The small-angle-break problem? The buckling problem? We had one, maybe two homework problems on these rather obscure topics. I agree they're important, but so much that we are responsible for memorizing them? It would have been fine if we had been given the applicable formulae and preparation during the semester, but to expect us to work them from memory after having only brushed on these topics is absurd. In previous classes I took, each professor asked questions in pre-lims throughout the semester about topics he or she felt relevant to the course. When it came time to have the final, it consisted of topics similar to what was required for the pre-lims and got at the core of the material of the course. It seems that you wrote this final to try to cover gaps that your pre-lims left in the course material. Though we had covered buckling and four bar linkages by the time of the second pre-lim, there were no questions even close to these ideas on the second pre-lim. These types of problems were either too complicated to require students to work during an exam, or were too miniscule to require memorization. The absence of such problems in the second pre-lim and the presence of other problems on that second exam gave us a framework of material and concepts to focus on in preparation for the final exam. In other words, I tried to study for your final exam as I have successfully!! studied for all of my other Engineering finals: I studied the concepts you emphasized on exams in preparation for the final. And I feel as though you intentionally misled the class and tried to "trap us" by testing us on complicated concepts on the final that you did not test us on earlier in the course. If you wanted us to solve problems requiring this much focus and detail on exams, I feel that you need to set more clear expectations of us and more complete direction in your course and on your exams throughout the semester. All in all, I was very displeased with the way you tried to asses our understanding of the course material. Consider that this exam does not properly reflect our knowledge of the course material when computing our final grades.

Ruina responds: We tried to design the exam so that if you could do all of the homework and explain it to a friend you could do all the exam. I think we did that. We did not have a sinister intent. Please look at the solutions and see if you think that the required work is beyond what someone taking this clase should be able to do. No tricks. No strange cases. No hard calculations. No peculiar things to memorize. Lots of things that are like the homework problems, the previous prelims, and the lecture examples. We tried to write an exam that emphasized basic mechanics, and would reward people who spent time thinking hard about the material.