## Unit 19 buzzing along nicely

Lots of the mechanics that first baffled me early on in the course are developed and extended in unit 19, of which the mission appears to be to derive ways to model several particles and, er, big things around a centre of mass.

Linear algebra required, a good memory for several previous units also required.

Larger jumps in the algebraic resolution of problems, as is to be expected at this point.

In fact, there’s an awful lot squeezed into just four chapters this time round.

Looking at the assignment questions, I can actually answer one using a result derived back in 1984 in pre-O level physics.

I still remember my old physics teacher, Mr Briggs, reinforcing this one.

Sadly, I don’t think quoting a one line theorem in “school level” words is quite what’s needed though to solve this to the OU’s satisfaction. Still, at least I know what the answer has to be…..

In other news, my completed assignment question for unit 18 continues to play at the back of my mind – well, a one mark sub-part near the end of the question which is technically answerable from a standard course result published within the unit does.

Me being me, though, I’ve had to go the long way round and end up with three pages of A4 just to check my answer. And I’m still not convinced. Hmm.

In even further news, I officially have a trapped nerve in my neck. It’s playing merry hell when it detonates every three or four days and some brief physio work hasn’t sorted it out. The worrying bit is that when it does go off, the left side of my face goes a bit numb for a day or so afterwards. The doctor has ruled out anything more than a trapped nerve though, so I guess I just need to throw a couple of hundred ££££££££££££s at the physio instead. Painful in both neck and wallet, and I have resolved to buy some new pillows next time I’m in Tesco.

Not that you needed to know that. 🙂

## Unit 18 dusted

I had a day of no noise, no computer and no phone.

It translated into 10 hours straight of unit 18 – just finished now.

The assignment question looks ok for the most-part, touch wood (taps head).

I should start unit 19 on Monday, which puts me two days behind the course calendar.

Off out to walk the dog, then play the usual game of Foster’s versus John Smith’s vs Old Speckled Hen. Then off to bed armed with an old MS221 DVD I’ve found, just to rewatch the video lectures that made my brain cringe and cry two years ago. I expect them to be pretty “standard” now.

Progress, and all that.

I’ll also order a book on biomechanics I was made aware of a while back – it’s on the recommended pre-reading list of a couple of biomechanics MSc courses running in the UK and applies, in the main, Newtonian physics to modelling the motion of living creatures – mostly humans. Looks interesting.

Also on the order list are a couple of physics books recommended by Chris over at his blog

( http://chrisfmathsphysicsmusic.blogspot.com – see the RHS of this page for a live link).

## 12 hours straight (nearly)

Feeling quite chuffed with myself today.

Stopped twice for 10 minutes to check my emails and have a quick check of my favourite internet blogs, and stopped once for food for 20 minutes.

The rest of the day has been spent immersed in unit 17, filling in every gap where a large amount of algebra is left out of the book (the unit emphasizes getting a handle on the physics rather than the diff eqs).

I’ve solved some horrible particular solutions today. How many “omegas” can you fit into one solution? Blimey.

The pay-off for this hard-work?

1) a headache

2) thoughts that someone put my clock forward, since the whole day has just shot by

3) halfway through the first TMA question. I expected to start it tomorrow.

Some videos to accompany this week’s learning:

Now only 2 days behind the course calendar.

I think I’ll batter on with unit 18 between Monday and Friday and see if I can close the gap to zero.

Whether it’s a good thing, or not, I’m addicted to all this maths.

Bedtime reading tonight should involve making a start on the third unit of M343 – applications of probability – I’ve bought secondhand books for that, MT365, and the third-level optimization course. Good idea really, as it’s confirmed that I don’t want to do the optimization.

I got the books for a very reasonable price from: http://www.universitybooksearch.co.uk/

## Eureka moments – and satisfaction

I suppose if you’re reading this blog, you either study maths/physics with The Open University, or got lost on your travels around the internet.

Assuming it’s the former, then you’ll probably agree that there’s something immensely satisfying about working something out for yourself – particularly when you’ve found the concept / method / thing awkward / difficult / impossible to begin with.

It didn’t make you financially richer, didn’t get you a promotion at work and, on the face of it, was probably a lot of time invested for one tiny step forward.

But it does feel good.

So, unit 17 has clicked into place and lots of things are linking up. My mathematical modelling molecules are starting to take the shape of a very basic life-form.

This week has been a differential equations party (real and complex), an algebra feast, and a bit of a head-scratcher.

The unit has introduced the ideas behind strong, weak and critical damping, the “model damper”, systems analogous to the model damper, combination damping, the damping ratio, a method of using the quadratic discriminant to investigate damping levels / strengths, decaying amplitude, forced damping, forcing by displacement, steady state solutions, magnification factors, resonance and, of course, methods to model, investigate, and objectively analyse, both quantitatively and qualitatively, all of the above.

The TMA question was not what I was expecting. I am peering at it with a quizzical eye.

That, alone, will not be enough, however.

I have one large study session to go on unit 17 – ie all day tomorrow – then on to the TMA question on Sunday – probably all day as it’s worth 32 marks out of the 95 assigned to the maths in the TMA. Yeeeeeeeek. (The other 5 marks go on presentation, presumably in an effort to help retain the sanity of the tutors who have to mark questions which can range over 10 or more pages, which would be a bit of a drag if the whole thing was just slapped together without breaks, explanations, justifications and neat writing / typing / LaTeX).

So, with 20 minutes down time before walking the dog, I’m sitting here pondering something that’s being pondered on at least two other OU maths blogs right now – is the chase for cracking TMA marks coming at the expense of deep learning?

By that, I mean, is obsessing over the TMA costing time otherwise available to get an even deeper understanding?

I like to think I’m logical and can crack most problems. But I also have a **** memory.

Or do I?

Maybe I just concentrate on cracking the problems and not on really learning the material?

Who knows?

I’ll find out soon enough in the exam, but it does concern me.

I dislike the fact that I can barely remember the linear algebra from M208 last year although, curiously, almost all of the group theory and real analysis sits fairly fresh in my head.

Maybe the factor of “interest” comes into play here.

I found linear algebra boring but liked the other components.

With MS221, I liked the calculus and complex number stuff, plus some of the conic stuff. I disliked the number theory, recurrence relations and several other things.

Guess which I can remember?

So, how come I like everything in MST209, though I’ve found some of it very difficult, yet don’t seem to remember bits of it already?

Is it because it’s vast?

Is the learning pace too swift for me?

Or am I dealing with it like it’s a course of here-and-now problems to be solved – ie TMAs – as opposed to a blueprint to a mathematical skill set?

I’d be interested in other students’ thoughts – is the course so huge no one can take ownership of it first time round, or have I evolved into a TMA-completer who doesn’t know the subject?

## TMA 4 result back

Again, very quick and thorough marking by my tutor.

Some red pen in discussing sig fig vs decimal places in the way I have presented one of my answers, which I’ve taken on board.

Very high pass one again.

All good.

The mark has inspired me to crack on through block 5.

So, from now (well, 6pm) until Sunday 11pm is planned maths time.

I’ve had a quick look at the work for next week – unit 18, which is called “Normal Modes” – and it appears to deal with oscillations via eigenvalues and eigenvectors. Should be interesting.

## Unit 17 – lots of work

Unit 17 is, so far, a large exercise in differential equations, logs, largish algebraic rearrangements, lots of setting up models, and lots of calculator work.

It’s all quite followable, line by line, but by the time I get to the end of it all and proudly proclaim my answer to some sub-part I was solving, I end up realising I’ve lost my train of thought about the question as a whole.

My advice to me, come revision time, is to run a side margin of notes of what you’re aiming at, what you know, and how best to manipulate the coordinate system to start off with easy initial conditions.

I have an earlier start than normal for work tomorrow, so jumped on here just to update quickly and say – this chapter is time-consuming.

Five hours tonight has only brought 7 pages of progress. Bah. The text is getting dense, the algebraic leaps ever greater, and I could really use a week off to get through it.

This will be the first point at which I fall behind in an uncomfortable way on this course.

With little else to chop out of my daily calendar to accommodate study, I suppose sleep is the next thing to go.

Advice to next year’s students – use the time gained in the relatively short units 15 and 16 to get ahead on chapter 17. And make sure you can solve inhomogeneous diff eqs off the top of your head or you’ll get seriously slowed down since this is one diff eq festival.

Bloody decaying oscillations and failing buffers – easy enough to assess quantitatively but a pain to assess qualitatively.

## CMA results out

Hmm, two questions wrong.

I’ll check one of them in a bit – I thought my answer gave a solution but obviously not – will try it again, then try the answer given by the OU, then store that in the brain cabinet marked “do not ever forget this again”.

The other answer, well, I’m mystified. No doubt the OU is right, so it does mean I have a fundamental error in the way I solve a certain type of mechanics question.

And that needs ironing out sharpish as well.

Today’s planned activities have just warped into “sort these gaps out”.

Good luck to all as they pick their results up today.

## TMA4 and the first CMA – done

I submitted the first CMA (computer marked assignment) a couple of weeks ago.

Last night was the cut-off point.

In the 22 hours since that cutoff point, I’ve worn out my refresh button waiting for the results which, I had assumed, would be immediately forthcoming given that a computer “marks” the submission.

They haven’t been and a message says: “Awaiting Feedback”.

Why the impatience?

Well, because the CMA assesses our knowledge of the first half of the course and I deliberately completed it without referring very much to the course notes.

It’s my test of whether I’m understanding and retaining the material.

I’ll give it until five-past-midnight tonight…. not that I’m impatient or anything…. before going to bed.

TMA 4 is sat here waiting to be posted – unit 16 was also straightforward – but I’ll do my usual trick of leaving it a couple of days, then checking it over before sending to my tutor.

And, so, on to unit 17, which I’ll start on Sunday since Saturday = digging up the garden prior to turning it into a modern wilderness of waterproof membrane beneath three tonnes of decorative gravel.

Unit 17 is titled “Damping, forcing and resonance”. And that’s as much as I know since I haven’t opened it yet (opening it requires finding the Block 5 book, which is, er, somewhere).