maths study via The Open University

Archive for September, 2011

Final TMA back

Some marks deducted.

One disappeared for subtracting one number from another – and getting the wrong answer :-).
One got taken off for misinterpreting one of the easier revision questions and giving a bitty answer.
And two got removed for failing to complete a question in the OU way, despite arriving at the right conclusion.

Pass one on the assignment side of things.

Now “just” need 85%+ in the exam.


SM358 glossaries

They live here and here and give a bit of a clue to what is studied.

Some videos relevant to Unit 28 (and Unit 27)

These helped.




Still to watch, largely out of interest:

Unit 28

Ok, so deriving Kepler’s Laws of Planetary Motion relied on Kepler having 40 years of astronomical data from which to draw his conclusions. Later putting it on a firm mathematical footing needed one Isaac Newton to reinforce it with calculus.

I have neither 40 years of data nor a Sir Newton to draw on between now and next week. 🙂

The alternative is therefore Unit 28 of MST209.

But Unit 28 requires your calculus to be in tip-top condition – not so much the skills of doing it, as some rarely-used rules to be applied at various stages of the derivation.

I thought my calculus was quite good, but, at one third the way into the unit, with all exercises tried, and some failed, I have a lonnnnnng list of questions to ask my tutor on Monday.

I suspect he’ll groan internally when I phone him, since I’ve phoned five times in the past week already about fairly abstract thoughts on previous units, all of which have been borne by my propensity for making solutions to questions more involved than they need be (I once submitted two pages of a proof, which came back with his proof, in agreement, which was about five lines long).

But he’s a jolly good egg, with patience far in excess of mine, so all will be ok.

In the meantime, soldier on, I shall, with the aim to have Unit 28 finished by 11:59pm on Monday night, the TMA in the post, and the CMA submitted via the course’s electronic system.

Tuesday evening can then be spent catching up on things for work, before Wednesday marks the start of MST209 exam revision proper.

Unit 27

Unit 27 is about rotating bodies and angular momentum.
I keep getting confused.
The maths is simple enough – it’s the remembering what is what that’s the confusing bit for my decaying brain.

In particular, I keep confusing angular momentum with angular velocity.

Angular velocity is intuitively easy to visualise. Angular momentum seems less so – probably because I haven’t found a nice one-line nutshell that nicely describes it.

So, angular speed, angular velocity, position vectors and their derivatives, the torque law for “n-particle” systems, moments of inertia, cross products, Newton’s Third Law, circular motion, simple trigonometry, and lots of other things we’ve met so far on the course have all landed in Unit 27 for one gigantic party.

I’m just finishing section two now, with section 3 (angular momentum/moments of inertia/parallel axes theorem/kinetic energy of a rotating rigid body) and section 4 (torque law relative to the centre of mass/decomposition theorem/rolling objects) to come between tomorrow evening and Saturday afternoon.

The assignment question is massive – in word length, number of sub-questions and overall marks toward the final TMA.

I’m somewhat scared.

Unit 26 – someone beam me up

Very well-written and exhaustively coherent learning material, but the topic is dry.
Numerical methods for diff eqs.
Not loving it.
I keep glancing at the calendar. MST209 is getting painful now.
And the schedule is nuts in the final month.
It’ll only leave me three weeks for revision of the 1200-ish pages before the exam.
Same boat for many, I expect.