Non-uniform circular motion (3 Viewers)

[bobohappy]

hey there,

just wondering if any 4U teachers at your school teach 'non-uniform circular motion'??? as part of the mechanics section,

i realise that its in none of the textbooks, but apparently you still have to do it??????? i believe it was in one of the BOS past papers

any clues?

 

[Drongoski]

George Fisher's Senior Maths Notepad Study Guides on "4 Unit Maths" (Phoenix Education) - 1996 has a treatment on it. Don't know if any latter-edition of this exists from Phoenix.

 

[gurmies]

hey there,

just wondering if any 4U teachers at your school teach 'non-uniform circular motion'??? as part of the mechanics section,

i realise that its in none of the textbooks, but apparently you still have to do it??????? i believe it was in one of the BOS past papers

any clues?

Mine said it's not examinable. How valid that is, i'm not sure.

 

[Iruka]

You could check the syllabus to be sure.

 

[cutemouse]

There's a bit that can be examined... But only asked once in the 1981 HSC, when the course was first introduced

Although it was examined once 28 years ago... it also happens that the calanders every 28 years are the same... so you never know. That's what my teacher said anyway

The Coroneos 4U supplement treats this aspect nicely.

 

[yibbon]

I can't see anything in the syllabus about it, I'm not going to study it. Have enough trouble with the uniform stuff anyway

 

[untouchablecuz]

which year was the non-uniform circular motion? i've done alot of papers and i've never encountered it

 

[cutemouse]

I can't see anything in the syllabus about it, I'm not going to study it.

That's just plain stupid then, and it IS in the syllabus. You need to be able to answer the question as below...

which year was the non-uniform circular motion?

In the 1981 HSC 4U paper.


---
A point P is moving in a circular path around a centre O. Define the angular velocity of P with respect to O at time t.

Derive expressions for the tangential and normal components of the acceleration of P at time t.
--

 

[gurmies]

Ah, yeah. We did that question as part of our notes =]

 

[untouchablecuz]

is this how you would do it?

not too sure about the normal component of the acceleration

edit: hmm, i dont think i have resolved my vectors correctly

 

[untouchablecuz]

what about

v=dL/dt, where L is the length of the arc and v is the tangetial velocity

but L=rx

v=d(rx)/dt=r(dx/dt)=rw

tangetial acceleration=d(rw)/dt=r(dw/dt)

correct?

 

[Trebla]

You basically determine your acceleration in the x and y directions before resolving them both in the tangential and normal direction (the whole right-angled triangle with basic trig). Then you add/subtract the relevant vectors and their corresponding equations to obtain an expression for tangential and normal acceleration and hence their forces. You should notice that the normal force is negative, therefore it is actually directed towards the centre (i.e. centripetal force).

 

[cutemouse]

As I said before, the Coroneos 4U book treats this aspect very nicely.

 

[kaz1]

My teacher said that they can only examine you on circular motion questions with constant acceleration.

 

[cutemouse]

My teacher said that they can only examine you on circular motion questions with constant acceleration.

Well then your teacher is wrong. See my previous posts. You need to be able to do that question.

 

[kaz1]

Well then your teacher is wrong. See my previous posts. You need to be able to do that question.

lol,just letting you know my teacher co-wrote Cambridge 4unit so I would assume she has a pretty good grasp of the syllabus.

 

[Aerath]

lol,just letting you know my teacher co-wrote Cambridge 4unit so I would assume she has a pretty good grasp of the syllabus.

Cool. I say your teachers wrong too. Is your teacher Denise Arnold?

 

[cutemouse]

lol,just letting you know my teacher co-wrote Cambridge 4unit so I would assume she has a pretty good grasp of the syllabus.

Just to give you some idea. Our main textbook is Cambridge. But for this topic (Mechanics) we didn't use it

 

[kaz1]

Cool. I say your teachers wrong too. Is your teacher Denise Arnold?

Yes.

Just to give you some idea. Our main textbook is Cambridge. But for this topic (Mechanics) we didn't use it

I'll try and self learn it then just in case they ask it.

 

[cutemouse]

I'll try and self learn it then just in case they ask it.

Good idea