[sonofdot]

Apologies if there's already a thread for this exam - I did a brief search, but you know what the tsr search function is like...

Anyone else sitting it? I did a paper today and did pretty well on it - I think I need to go over vertical circular motion again. How's everyone else's mechanical fun revision going?

And nuodai, I want your comic up here, you know, for inspiration... (although maybe it is too lewd for TSR's innocent ears...)

[nuodai]

PAIN! FEAR, PAIN, DEATH, DOOM, AND ANGER!

M3 is hated by me.

Thy requested comic is more or less what I was doing when I should have been revising for M3. Indeed, it is partially revision in itself, but of a more... crude nature.

[NesQuiK.]

Originally Posted by nuodai

PAIN! FEAR, PAIN, DEATH, DOOM, AND ANGER!

M3 is hated by me.

Thy requested comic is more or less what I was doing when I should have been revising for M3. Indeed, it is partially revision in itself, but of a more... crude nature.

at the m3 comic, thats sik!
How you coping with all the exams? I've got a couple more than you and its getting pretty intense for me!

[nuodai]

Originally Posted by NesQuiK.

at the m3 comic, thats sik!
How you coping with all the exams? I've got a couple more than you and its getting pretty intense for me!

The way I see it, my entire fate [uni-wise] relies on two horrible, disgusting, evil Psychology exams which involve solid essay-writing for 1.5-2 hours and have very dodgy mark schemes and very dodgy examiners. FP2 and FP3 went quite well, so Maths is alright (I'm doing 13 modules anyway, so it's the best 12 out of 13 so I can afford to screw up one or two). M3's actually starting to fall into place now (about bloody time), so with any luck I might even have a shot at doing some Mechanics questions in my STEP exams.

So really it's just Psychology Units 4 and 5 that are going to kill me. The Psychology AEA, French exams, General Studies exams, STEP I and D1 aren't causing me much stress at all. STEP II and M3 are tougher maths-wise, but I should be alright with them.s

The thing I'm having trouble getting my head around at the moment is weird systems where you have an object attached to a spring on a rough sloped surface moving with simple harmonic motion... my brain boggles. Similarly for vertical circular motion of a particle attached to a string, when I have to consider when the string becomes slack. I'll get my head around it somehow...

[Xei]

I'm concerned about M3... mainly because we don't seem to have learnt anything new? I don't know what I'm supposed to know. :l

I'd be really grateful if somebody could provide a list of the types of questions we have to be able to answer..?

But yes, there's the new calculus stuff which is always extremely obvious after having done the much harder differential equations of FP3 and the single new thing is that a = vdv/dx, there's the momentum stuff which is literally nothing new at all except resolving, there's the vertical circles stuff which is nothing new at all (do them all by energy...), there's the springs stuff which is just two new formulae, and there's SHM which you can work out entirely from the equation x = asin(kt+e)...

The lack of anything really new makes me feel like I'm missing something. :l

[nuodai]

Originally Posted by Xei

I'm concerned about M3... mainly because we don't seem to have learnt anything new? I don't know what I'm supposed to know. :l

I'd be really grateful if somebody could provide a list of the types of questions we have to be able to answer..?

But yes, there's the new calculus stuff which is always extremely obvious after having done the much harder differential equations of FP3 and the single new thing is that a = vdv/dx, there's the momentum stuff which is literally nothing new at all except resolving, there's the vertical circles stuff which is nothing new at all (do them all by energy...), there's the springs stuff which is just two new formulae, and there's SHM which you can work out entirely from the equation x = asin(kt+e)...

The lack of anything really new makes me feel like I'm missing something. :l

M3 is largely an extension of M1 and M2 topics with a bit more calculus, so by the sounds of it you're more or less there!

[sonofdot]

to keep this thread up there...

I was doing some good M3 revision today. I did the Jan 07 past paper and I think I did pretty well, so I'm feeling pretty confident. I do seem to have a tendency to make little errors in SHM questions though...

[Xei]

I'm confused about bouncing objects in momentum questions... I thought you have to use the fact that the impulse acts in a direction parallel to the surface; however, in Jan 07 and an older paper, it asks you to find the angle of the impulse..?

[sonofdot]

Originally Posted by Xei

I'm confused about bouncing objects in momentum questions... I thought you have to use the fact that the impulse acts in a direction parallel to the surface; however, in Jan 07 and an older paper, it asks you to find the angle of the impulse..?

(I presume you mean the impulse acts perpendicular) In my textbook it says the impulse is perpendicular only if it is a smooth ball and a flat surface, so maybe that wasn't the case in this question...

I guess maybe you can assume that the impulse is going to act perpendicular to the surface unless it states otherwise...

[Init4Beans]

Originally Posted by sonofdot

(I presume you mean the impulse acts perpendicular) In my textbook it says the impulse is perpendicular only if it is a smooth ball and a flat surface, so maybe that wasn't the case in this question...

I guess maybe you can assume that the impulse is going to act perpendicular to the surface unless it states otherwise...

I remember that question. I agree with you son, unless it states impule is perpendicular.

All you had to do for the other one though is split impulse into hz and vert components.

Sitting m3 tomorrow, feeling alright.. Been getting mid 60's on papers which is good enough for me.

Just hoping there's not something out of the ordinary like there seem to have been on the other OCR papers this year.

[miphistor]

I'm crapping myself about this exam.... need an A in further maths to get into warwick and I thought that FP3 didnt go too well, so i have to make it up =(
Better go revise....

[around]

M3 could either go really badly or really well, depending on what questions come up.

I mean, like, some people can 'see' mechanics, I just can't

[sil3nt_cha0s]

HA! M3 - I don't need to do that. I did D2 instead, and it was definitely much easier than M3's going to be!

[Xei]

I don't believe that D2 can be worth the same number of marks as FP2, it's ridiculous.

[sonofdot]

Best of luck everybody!

[sonofdot]

So what did people think? Personally, I thought it went pretty well All the questions seemed fairly "normal" and similar to the past paper questions, unlike other OCR exams this year... I finished with about 20 minutes to spare which is always a good sign.

[nuodai]

Holy jeebus, I might not have failed! After the FP2 exam I didn't know what tricks OCR were going to pull, but those questions were pretty much straightforward. Admittedly, I ran out of time on the last part of the last question, and I messed up the first couple of parts because of having a sign wrong, but I may have done a lot better (i.e. an A/B) than I thought I would (C/D).

[sonofdot]

These are the numerical answers that I can remember, if you want to compare/tell me where I messed up...

1) e = 0.5, impulse = 2.7Ns vertically upwards

2) weight = 15N

3) angle 60 degrees below line of centres, e = 0.5 (again?)

4) v = 32.2m/s

5) max tension = 12N, speed at M 3.66m/s

6) can't remember...

7) final part:

[robster113]

My answers

1) (i) 0.5
(ii) 2.7 (along line of centres (vertically upwards))

2) (i) 14N
(ii) 15N weight

3 (i) 60 degrees
(ii) 0.5

4 (ii) 32.2

5) (i) 12N

(ii) b) 3.96

6) (iii) 0.8m
(iv) -0.0385, 1.10s
(v) 0.0893

7) (i) v^2 = u^2 - 2ga(1-cos(theta))
(ii) 5ag
(iii) (2-root3)ag

[nuodai]

I've forgotten most of my answers, but I definitely got the same answers for part 1, 2, 3 and 6 as you two above, which is a good start