Vectors (1 Viewer)

Isomorph

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Hello,

What do you all think of the new vectors topic?

I'm not sure quite what to make of it. They seem to really like intersection questions (where you simply solve the simultaneous equations), but other than that and geometry questions (limited to parallel and perpendicular lines, proving equal angles), what else can they ask?
 

CM_Tutor

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Mechanics questions using vectors, for a start, and other Physics-like problems
 

Isomorph

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From what I have done so far, mechanics problems incorporating 2D vectors in the new syllabus are restricted to projectile motion, which usually can be solved by resolving the vectors into components and solving independently.

Have you come across any non-standard mechanics problems that are hard due to the presence of the vectors?
 

CM_Tutor

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From what I have done so far, mechanics problems incorporating 2D vectors in the new syllabus are restricted to projectile motion, which usually can be solved by resolving the vectors into components and solving independently.

Have you come across any non-standard mechanics problems that are hard due to the presence of the vectors?
I think there is plenty of scope for being creative in asking vector-based questions. We don't have hundreds of past trial papers to look at for the challenging questions that will emerge over the next few years.

One concern that I have is that problems like projectiles have been done at HSC level for decades without vectors, and I suspect there will be some who take a projectile vectors question, translate the problem into a non-vector form, solve it, and then try to transform back. This will cost them time in exam situations, risks errors in translating, and risks forgetting to back-transform to answer in vector terms (when that is required). I can't think of any problem which could only be done by vector methods, or indeed, could only be done by non-vector methods. I can think of cases where one is easier than the other, however.

It's worth bearing in mind that all the teachers, tutors, past papers, etc, have thought in non-vector terms for years and so habits exist that current HSC students will be exposed to but need not adopt. I have many years of tutoring experience at HSC level and I had to sit and work at some projectiles vectors questions forcing myself to stay in vector mode even when I knew immediately how the answer would work without vectors. In short, any times there is a significant syllabus change - and this is the first in a very long time - the new areas will be less familiar / comfortable for those who are used to the old syllabi and will produce unexpected / unanticipated questions both from students and in looking at assessment tasks. That may seem unfair to the first cohort, but in reality it just means that "teething problems" will be smoothed out through scaling and moderating, etc.

MX2 has had some controversial exam-related situations over the years, but hopefully they will not be repeated.
 

CM_Tutor

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Added thought: vectors come up in complex numbers, too, where non-vector solutions are often more complicated / messy. A simple example being:



Try it with and without vectors and I hope you can see what I mean. :)
 

HeroWise

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Not that bad actually. Square both sides and you come to the conclusion that: xu+vy=0 .
z/w the real part is (xu+yv)/(v^2+u^2) and that's 0 hence purely im
 

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