scott wrote:
>>> Kinematics and Dynamics in 2D
>>
>> Kinematics is a word?
> 
> Yes, it's basically about movements of objects without considering the 
> forces that cause the movements.  eg if one part is fixed to move at 
> 5000rpm what happens to the rest of the connected system.  Quite a lot 
> of geometry and resolving velocities, instantaneous centres of rotation 
> etc.

So if you wanted to describe the motion of a complex arrangement of 
rigid components (e.g., a car gearbox), you'd use kinematics?

>> Any idea what a "resonant mode" is?
> 
> One particular way something can vibrate, that can't be split up 
> further.  A bit like splitting a signal into sine waves.  eg take a 30cm 
> ruler, you can bend it in the middle, that's the 1st mode.  The 2nd mode 
> is to force it into a complete sine wave shape (ie two bends in the 
> length).  Of course in 3D you get many more modes, like twisting, 
> bending in the other direction etc.  It's easier to analyse the system 
> if you can split it down into the resonant modes.  Each resonant mode 
> will also have a natural frequency.

So... the resonant modes of a effectively 1D system (a string, a 
gas-filled pipe, etc.) would just be harmonics of the main resonant 
frequency?

>> Ouch. AFAIK, anything involving fluids or gasses = highly complex.
> 
> Yep this was my worst course, working out the states of steam and water 
> vapour as it goes through a cycle, using huge look-up-tables because 
> there are no formulae for these highly complex things, etc.  Although 
> learning exactly how a jet engine works and calculating the exit speed 
> and temperature of the exhaust gases was pretty cool.

Heh. So you know how an ideal gas is different from a real gas then? ;-)

>>> Materials I & II
>>
>> Now that *sounds* quite simple... but I bet it isn't.
>>
>> (I'm presuming this is about elastic vs plastic deformation and so 
>> forth.)
> 
> Yeh, and how stress and cracks propagate, phase diagrams of mixtures of 
> materials, particularly on the iron-carbon one (there are like 100 
> different states of iron depending how quickly it is cooled and what 
> proportion of carbon you have in there).  Also hardness of materials, 
> statistical analysis of ceramics, that sort of thing.

Perhaps you could explain something to me then:

If I take a piece of paper and hold it horisontal, it flops under its 
own weight. But if I fold it down the middle, now it *can* stand up 
under its own weight. (But only if you hold it the right way.)

At the same time, a straight metal rod is very strong, but once bent it 
becomes drastically weaker, and it seems that nothing will restore it to 
its original condition.

>>> Comms Fourier Transforms & Signal & Data Analysis
>>
>> What a title! o_O
> 
> Got very hairy at stages with things like cross-correlation and 
> auto-correlation, also with things like z-transforms and FIR and IIR 
> filters etc.

Now that really does sound interesting! Heh.

I still have trouble getting the fine technical details of DSP straight 
in my head. The basic principles are quite simple - once somebody 
explains them properly - but minor details can make all the difference. 
(Is this a normalised or an un-normalised sinc function?)

>>> Mathematics
>>
>> Oh... so that's specific then!
> 
> There were 2 courses here, both were optional depending on how much 
> maths you had done at A level.  Most people sat the "fast" course just 
> as a refresher, just to relearn the basics like how to solve 
> differential equations, how matrices work, stuff like that.

Wait - there's a way to *solve* differential equations?? o_O

I thought you just guess formulas at random until you happen upon one 
that has the desired properties - or more likely, use numerical 
simulation instead.

>>> Computing
>> Interesting?
> 
> Not really, software life cycle, structured programming, numerical 
> precision errors, algorithm complexity, search&sort algorithms, very 
> vague and general, clearly aimed at writing some small code block to 
> solve an Engineering problem rather than any huge software project.

Floating-point arithmetic is a non-associative algebra. Isn't that sad? :'(

>>> Structural Design Project (ie building a bridge!)
>> LOL!
> 
> They applied prices to each bit of metal you could use, then you had a 
> budget to build a bridge to span a certain gap (about 1 metre) and 
> support a certain weight (about 150kg).  Of course the cheapest one that 
> could withstand 150kg won.  Mine buckled and collapsed spectacularly at 
> about 70kg due to me not actually putting it together very squarely.  I 
> still have this twisted lump of rusting metal in the attic at home!

Niiiice...

I wonder - can I find it on YouTube? Hold on a sec...

...yep, I found it:

http://uk.youtube.com/watch?v=-fE5ZE4Pj5w

PROPPER JOB!!

OMG, the first time I watched this on TV, I killed myself laughing. All 
those hours to build, and it ****ed itself to pieces in seconds! :-D

>> The... uh... no, I can't remember the name of it. But there *is* a 
>> programming contest that's a bit like the IRTC. They set a challenge, 
>> and you have so many days to write a program that solves it. One of 
>> them was where your program accepts a track description as input, and 
>> produces a series of driving commands as output. The car that gets 
>> round the track fastest wins. (But the car simulation part is an 
>> external program, with limits on acceleration, cornering, etc.)
> 
> Oh that sounds cool, one of our practicals was a bit like that, we had 
> to write a program to control some factory that was producing several 
> different parts according to demand.  It got quite complex and remember 
> writing a 6 or 8 dimensional optimisation algorithm to see when was best 
> to switch production lines from one product to another!

...I DID THE WRONG DEGREE! >_<

AND I'M IN THE WRONG JOB NOW... :'{

By the way... how much of the stuff you learnt do you actually *use* now 
anyway? ;-)

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