**Subject Code/Name:** ENGR20004 Engineering Mechanics **Workload:** 3x1 hour lectures, 1x2 hour workshop per week

**Assessment:** 30% on 3-4 assignments, 15% on MST, 5% on weekly quizzes, 50% on final exam

**Lectopia Enabled:** Yes, with lecture capture

**Past exams available:** A couple available on the exam archive but none given. Note that different lectures = different style of questions.

**Textbook Recommendation:** None prescribed, Meriam JL and Kraige LG, Engineering Mechanics : Dynamics 7th Edition and HGibbeler RC, Statistics and Mechanics of Materials 3rd Edition recommended on the website but I wouldn't say you need them. Questions for practice are from the textbooks anyways.

**Lecturer(s):** Christian Brandl for Statics/Solids, Bagus Nugroho for Dynamics

**Year & Semester of completion:** 2020, Semester 1

**Rating:** 3.5/5 online. 4/5 if in person.

**Your Mark/Grade:** 77 (H2A)

**Comments: **Note that I took this subject during 2020 where everything's online so it may be a slightly different experience to what others might experience.

There's a lot to go over in this subject but like what you might've heard or seen, this is not an easy subject. It's difficult, no doubt. Maybe the most difficult in my undergrad so far. Yes the likelihood of someone failing isn't impossible. Yes people have dropped out or redone the subject. But don't let that scare you too much. It is possible to get through this subject, it is possible to do well and maybe even enjoy this subject.

CLASSES AND ASSESSMENTSLectures

The lectures are taught by Christian for Statics/Solids and Bagus for Dynamics, and are in a format where the first 2 essentially teach the week's content and the third lecture is reserved for examples about what the first 2 lectures teach. In online teaching, the first 2 are recorded and sent at the beginning of the week, and the 3rd is a webinar with the lecturer to ask questions. While you might think that this means there is not as much to learn, trust me when I say that this is a lot, and I mean a LOT of new concepts and content. Something I would recommend is just making sure you redo the questions from the lecture by yourself. It's easy to just go and say "yeah I get this" but until you actually do it, you won't fully understand it.

As for the lecturers I found both Christian and Bagus to be quite friendly and engaging (well at least as well as it could be in online only). I did find Christian's methods and explanations a bit confusing at times. Bagus I felt was better and more clear in his explanations and working out. He also felt really relatable as he would talk about his past experiences as a student and just occasional stories about him, which helped keep the engagement and just made the subject better in general. There were some people that found Bagus a bit confusing, but I would attribute that more to just the dynamics topic itself.

Just a note that the subject content and difficulty can vary between lecturers so you may get a different experience.

Workshops

The workshop structure contains a mixture of prac weeks and non prac weeks. In non-prac weeks, the workshops run similar to that of a 2 hour tutorial, going through assigned questions with your group (explained in a bit) for 2 hours and working together either on the whiteboard, or in the case of online, in breakout rooms. In prac weeks, the 2nd hour is spent instead on the actual prac, which is kind of similar to ESD2 in the way it runs. However, in online classes there is just generally no prac week, instead a video of the experiment which is more of a simulation is sent to be analysed as part of the assignment.

And here is where I emphasise the importance of finding a good group. This is the group you'll be working with for the entire sem, including every week in the workshops and also in all the assignments. I was lucky enough to get really good group that I could work with, and because of that I enjoyed doing the assessments even if some of it was long and tedious. The workshops and breakout rooms were also more enjoyable because of this. However, I can see both the assignments and workshops turning into more of a chore or obstacle simply by having a bad group.

Assessments

The assessments consist of 3-4 assignments worth a total of 30%, a mid-sem test worth 15%, weekly quizzes worth 5% and a final exam worth 50%.

The assignments are what you would expect in engineering and mainly consist of analysing the theoretical parts of a concept and then comparing that with the experimental results. They are a mixture of maths and deriving, problem solving using learnt content and analysis of the experiment with MATLAB. It should be noted that MATLAB is a key component, and can be 30-50% of the assignment, so make sure someone in your group is comfortable with using MATLAB. You have approximately 2 to 3 weeks to do each assignment. It's a decent amount of work so don't leave it till the last day with your group. If you're online, I would highly recommend going into group zoom calls with your group throughout the assignment instead of just texting each other, it just helps a lot with communication.

The mid-sem was quite difficult with little time to work through questions. The topics based off the statics/solids section and made by Christian (who does favour making more difficult questions). For online, it was split into 3 separate mid sems worth 5% each. As I'll discuss later however, it can vary quite a bit between lecturers so you might have a different questions.

The weekly quizzes are well just that, 5 questions each week totalling 0.5% to basically "keep you engaged" in the subject. Some of these are more difficult than others but these questions are just off a textbook.

The final exam was more lenient in time than the mid sem but with a higher difficulty. I'll speak more about it in THE DIFFICULTY section.

CONTENT: STATICS/SOLIDS AND DYNAMICSThe subject is split into 2 sections, Statics/Solids and Dynamics. Statics/Solids are a follow up from ESD2 with an expansion of a lot of new content. The structure is as follows

- Week 1: Revision of ESD2 stuff (FBD, Method of Joints)

- Week 2: Method of Sections and Frames/Machines

- Week 3: SFD (Shear Force Diagrams) and BMD (Bending Moment Diagrams)

- Week 4/5: Stress, Strain and Poisson's Ratio

- Week 6: Centroids and Area Moment of Inertia, Flexure/Beam Bending

In terms of learning and understanding the content, the statics and solids parts are mainly alright (Weeks 1-5). They are a slight increase in difficulty from the mechanics section of ESD2, but it's not large and much of it just comes from the fact that there is a lot of new content involved. Week 6 however, does dial up the difficulty quite a bit with a lot of new concepts being introduced. This is where some integration or deriving may be applied, and can be a struggle at first to understand and apply. However, it is still doable with time and there are resources both provided by the subject (short video explanations) and also you can easily find some explanations online as well. This part is mostly okay, but as I'll explain later can actually be quite difficult depending on the questions (in THE DIFFICULTY).

Dynamics is where the scary reputation of engineering mechanics comes from. Like statics/solids, dynamics introduces quite a lot of new concepts. However, these are definitely harder to wrap your head around and can be quite confusing at times. The applying of these concepts is main difficulty for this section. The structure for dynamics is

- Week 7: Particle Kinematics and Coordinate Systems

- Week 8: Particle Kinetics and Work/Energy

- Week 9: Linear and Angular Impulse and Momentum

- Week 10: Free Vibration and Rigid Body Motion: Relative Velocity

- Week 11: Rigid Body Motion: Relative Acceleration, Instantaneous Centres, Equation of Motion

- Week 12: Revision

Weeks 7-9 are generally ok with a bit of time to understand everything. Application and general problem solving are the hard part, and unfortunately simply doing more questions does not have that same effectiveness as something say in prereq math subjects (Calc 2, Linear Algebra, Eng Math), although doing questions of course does still help. However, the topics in week 10 and 11 are where you'll find the most confusion. A lot of this will not have been anything you've seen before, and the content can be hard to understand at times. But once again, the real difficulty lies in the application and problem solving aspect.

THE DIFFICULTYAnd if you haven't noticed already, why engineering mechanics is so difficult is due to the application of these new equations and concepts that you learn, for statics and solids and especially for dynamics, NOT just the new concepts. Because of the high amount of new concepts, there are too many different types of questions that can be made and so many different ways to apply these concepts. Therefore at times, it can feel like there is a lack of a methodology or consistency when working through a problem. What I basically mean is that it won't be like say in ESD2 where if it asks to solve a truss system you automatically know the steps, method of joints -> find reaction forces -> FBD at each joint and use Fx, Fy, M = 0, at least not for much of it. That's not to say that there is no pattern or method to approach a question, for a lot of it there is, even for the harder topics like rigid body motion. But as I'll explain below, the questions can be adjusted to vastly change the approach and the difficulty.

The thing is with eng mech, is that it has an extremely high skill ceiling. The questions can be made to be however difficult a lecturer wants it to be, and there is no better example of this than on the exam. Before the exam, the lecturers, Christian and Bagus, said that they did not use the past exams as a reference, and it showed. Bagus said that the exam questions were going to be doable as long as you studied, and similar to that of the examples and questions they gave in lectures. And for the dynamics questions with Bagus this was true, most of Bagus' part was doable and similar to the style of the lecture questions, with enough difficulty to be able to separate the cohort of students. However, Christian's questions were not consistent with this, and so what ended up on the exam was that pretty much ALL of the statics and solids parts were actually harder than the dynamics portion. In fact, the hardest question of 5 on the exam was based off weeks 1-3, the easiest topics in eng mech. What I'm trying to say is that how difficult the subject is can vary greatly with the lecturer so it's hard to know what to expect even by doing past exams, as each lecturer has a different approach and difficulty and chooses slightly different topics.

TIPSAside from making sure you get a good group, redoing the lecture questions and not falling behind (you will die if you fall behind), I don't really have other suggestions I can give. From my experience, other stuff like the quizzes can also help with studies and so can the tutorial worksheets (both the workshop ones and separate tute ones). I found part A of the tute worksheets to be good in difficulty and manageable whereas part B I struggled with at times particularly for some of the topics. A lot of part B was harder than the exam but remember the difficulty would vary with the lecturer. Overall, just study however you can and try to find a method that suits you.

FINAL WORDSI guess to describe the role of the subject, it's best thought of as a stepping stone or a filter for future engineers. The problem solving and all those difficulties are what you would expect to have continuing forward, and for many this will be a good idea of whether or not you want to continue into engineering. I found the subject overall to be interesting at times, a good motivator and enjoyable. Other times I found it confusing, a demotivator and a source of stress. But ay, here I am, finishing this subject with no regrets and continuing in my journey to becoming an engineer. Like I said at the start, is this easy? No, definitely not. But is this doable? Yes it is. And can you find enjoyment in this subject? Through all of the confusion and difficulties, yes you actually can. This is one hell of a subject and I wish you good luck in getting to the other side!