* Applied Maths * predictions / discussion / aftermath (1 thread only please)

Geog ariphic · 22-06-2011 9:15pm

aranciata wrote: »

Are people predicting this paper to be easy or hard? Last years paper was a cinch in comparison to other years.. let's hope it's just getting easier cause I am hopeless at questions from earlier years! If it's anything like the first maths paper this year, I am going to die. I won't be able to cope with anything anymore and my heart will just stop beating.

WEeeellll apparently, there was a new chief exam setter (is that the word?) for applied maths installed last year, and he made it too easy. So if he wants to keep his job its gonna be like the pres and a right cúnt(i.e. v difficult)

aranciata · 22-06-2011 9:18pm

Geog ariphic wrote: »

WEeeellll apparently, there was a new chief exam setter (is that the word?) for applied maths installed last year, and he made it too easy. So if he wants to keep his job its gonna be like the pres and a right cúnt(i.e. v difficult)

Dear God. I don't care if the marking scheme will be lethal, I just want a paper I don't come out of upset/crying/devastated/traumatised..

yannfann · 22-06-2011 9:23pm

aranciata wrote: »

Dear God. I don't care if the marking scheme will be lethal, I just want a paper I don't come out of upset/crying/devastated/traumatised..

I'm coming out of that paper happy, regardless of the result, it means the LC is finally over. Well so long as I pass :P

HOPEd · 22-06-2011 10:43pm

Anyóne got any tips how to get an A1 in applied maths?? I really need it badly ...

LilMissCiara · 23-06-2011 12:18pm

Doing Q10 in 2008. For the first part you have to find P.

In the question they worked out F=MA (where A is in V), The Vs cancelled leaving P = 3200.

What I did was, we are told the engine exerts a constant power P and it is traveling on a straight level track. From this I said A=0, worked out that to get a value of V and put it in to F=MA.

I got the right answer (and I know it's a longer method) but the marking scheme doesn't have my method (I checked the alternative solutions as well)...

Would I still get marks for that?

aranciata · 23-06-2011 12:25pm

LilMissCiara wrote: »

Doing Q10 in 2008. For the first part you have to find P.

In the question they worked out F=MA (where A is in V), The Vs cancelled leaving P = 3200.

What I did was, we are told the engine exerts a constant power P and it is traveling on a straight level track. From this I said A=0, worked out that to get a value of V and put it in to F=MA.

I got the right answer (and I know it's a longer method) but the marking scheme doesn't have my method (I checked the alternative solutions as well)...

Would I still get marks for that?

Yeah you'll get the marks i'd say. My teacher has his own methods that he taught us himself, some are easier and some are a little longer but they always work.. and they're all i know!

So screwed for this exam.

LilMissCiara · 23-06-2011 12:29pm

aranciata wrote: »

Yeah you'll get the marks i'd say. My teacher has his own methods that he taught us himself, some are easier and some are a little longer but they always work.. and they're all i know!

So screwed for this exam.

Join the club..! :P But This time tomorrow.... We'll be finished forever!

aranciata · 23-06-2011 12:33pm

LilMissCiara wrote: »

Join the club..! :P But This time tomorrow.... We'll be finished forever!

Eh, not me I think! More like 2 months of torture & anxiety, then another 9 months of the LC! FML.

LilMissCiara · 23-06-2011 12:35pm

aranciata wrote: »

Eh, not me I think! More like 2 months of torture & anxiety, then another 9 months of the LC! FML.

I think everybody is saying that..! It's 7 weeks and 6 days until results..! :P

aranciata · 23-06-2011 12:39pm

Those are gonna be 7 long weeks!
I can take small comfort in that this week is finally ending, it's just been horrible..

magicianz · 23-06-2011 2:18pm

Quick question for anyone doing Q8, in the 2007 question the very last part of the answer is v=4w, v = 5.87 m/s, where did they got the 4??

Is it because the diameter of the circular movement of the corner 'C' is 4? Just thought of that while posting >.>

link to marking scheme/paper http://www.examinations.ie/archive/markingschemes/2007/LC020ALPO00EV.pdf

KoolAidRelic · 23-06-2011 3:08pm

LilMissCiara wrote: »

but the marking scheme doesn't have my method (I checked the alternative solutions as well)...

My teacher is one of the (few!) correctors for the paper and told us that the "alternative" solutions given in the marking scheme aren't all the alternative ones. At the marking conference yoke they might have came across a huge amount of other ways to solve them, but they don't all make it into the published marking scheme.

Any valid method will get the all the marks.

ride-the-spiral · 23-06-2011 3:08pm

It is indeed because the radius of the circle on which c rotates is 4, as v=radius x w

HOPEd · 23-06-2011 3:35pm

I really want to get an A1 cause I dont think I got enough points:( (never thought Id be relying on Applied maths:rolleyes:)
Im plannin on doin q 1,2,3,4,5 and 10 (cause those are the only ones our teacher did with us) Has anyone got any tips on how I could study??? I need a really good study plan ...PLESE help

aranciata · 23-06-2011 3:41pm

I'm doing 2004 Q2a at the moment... can anyone tell me why is the 22sinA=18sin45? Shouldn't the i values be equal, seeing as the bird has to counteract the push east it's getting from the wind? Doesn't the j value of the wind not help the bird?

KoolAidRelic · 23-06-2011 3:50pm

aranciata wrote: »

I'm doing 2004 Q2a at the moment... can anyone tell me why is the 22sinA=18sin45? Shouldn't the i values be equal, seeing as the bird has to counteract the push east it's getting from the wind? Doesn't the j value of the wind not help the bird?

That's the sine rule, not equating j's.

I did that question yesterday and said that the i's should be equal and opposite, which would be: 22cosA = 18cos45 (your way).
That'll give A as 55 degrees (North of East), whereas the marking scheme has 35 degrees (East of North). Either way works fine.

aranciata · 23-06-2011 3:54pm

KoolAidRelic wrote: »

That's the sine rule, not equating j's.

I did that question yesterday and said that the i's should be equal and opposite, which would be: 22cosA = 18cos45 (your way).
That'll give A as 55 degrees (North of East), whereas the marking scheme has 35 degrees (East of North). Either way works fine.

Ah I get it now. I got 55 degrees too, the marking scheme made it look like I was doing it wrong - we've never used sin rules! Thanks!

aranciata · 23-06-2011 4:16pm

I know i'm asking a lot of questions but this will be the last time I EVER will! Looking at the 2002 paper, there's a simple harmonic motion question in the middle of Q4... my class has never covered that, and we've only covered 6 questions so there's not gonna be any choice tomorrow... could they do that again?

epicwinning · 23-06-2011 4:36pm

aranciata wrote: »

I know i'm asking a lot of questions but this will be the last time I EVER will! Looking at the 2002 paper, there's a simple harmonic motion question in the middle of Q4... my class has never covered that, and we've only covered 6 questions so there's not gonna be any choice tomorrow... could they do that again?

They could. Even if you didn't cover it, all the formulae for simple harmonic motion are in the log tables anyway...

ride-the-spiral · 23-06-2011 4:37pm

I wouldn't worry about it. Apparently at the teacher's conference there was much anger towards the choice so I doubt they'd do something like that again.

LilMissCiara · 23-06-2011 4:50pm

Anyone in the same boat?

I do a question (say Q1), correct it and do well (well for me is 35m+). I move to the next year and get about 15m (in Q1)...

Tomorrow's paper better be fúcking good (and by good I mean have the questions I can do good in!)

aranciata · 23-06-2011 4:58pm

LilMissCiara wrote: »

Anyone in the same boat?

I do a question (say Q1), correct it and do well (well for me is 35m+). I move to the next year and get about 15m (in Q1)...

Tomorrow's paper better be fúcking good (and by good I mean have the questions I can do good in!)

That's definitely happening to me. I'm planning on leaving Q1 until the end cause it can be the most frustrating..

I'm focusing on Q2, Q3 (especially the inclined plane questions - my favourite) and Q10 cause they're quite formulaic and the methods can be pretty much learned off... hope I scrape a B2!

ride-the-spiral · 23-06-2011 4:58pm

Well you're recommended to never start with question 1 as it can be the most deceptive. And in terms of your timing problem, limit every question to 25 minutes, and if you finish a question in less time you can go back and finish any one that is incomplete. I know in an exam it seems so counterintuitive to just leave the question after 25 minutes, especially if you feel like you've almost got the answer, but just do it. In the end, you'll get more marks for drawing the diagrams and starting the equations of the next question than for the amount of time you might spend finishing off the algebraic part of your current question.

EDIT: I just realised that was not what you were asking at all... :P

deiseguuy93 · 23-06-2011 5:17pm

this is it guys! tomorrow is D-day and i would like to say good luck to all of ye! And have a great sessions afterwards!

LilMissCiara · 23-06-2011 5:19pm

I was using 1 as an example... It happens on all of them!

HOPEd · 23-06-2011 5:39pm

Pulleys and Wedges

Can anyone explain the concept of relative acceleration to me please? ... I dont get it...:eek:

Geog ariphic · 23-06-2011 5:47pm

2009: q10b (ii)

The marking scheme uses a tan formula in integrating, but i cannot follow it at all, and i ahve tried.
Can anyone shed light on what is going on in this one please?

LilMissCiara · 23-06-2011 6:09pm

God that's confusing..! :O

There is a formula in the log tables but that's for when X is on it's own... In this case X (or V) has a K..! :O

KoolAidRelic · 23-06-2011 6:17pm

It's a perfectly normal tan^-1 integral, albeit tricky to set up.

Multiply by 1/(k/k) and you get:
-1/k * 1/(g/k + v^2) dv

Which is a normal 1/(a^2 + x^2) with a^2 = g/k.

jamesr1775 · 23-06-2011 6:28pm

is projectiles tht bounce likely this year?

Geog ariphic · 23-06-2011 6:29pm

KoolAidRelic wrote: »

It's a perfectly normal tan^-1 integral, albeit tricky to set up.

Multiply by 1/(k/k) and you get:
-1/k * 1/(g/k + v^2) dv

Which is a normal 1/(a^2 + x^2) with a^2 = g/k.

While i try to figure that out - do you mean multiply above and below by 1/(k/k), or multiply both sides by it?

Edit:Ok right its a different way of multiplying by k above and below, gotcha.
If that's your definition of a perfectly normal integral, i hate to see what u consider difficult

is projectiles tht bounce likely this year?

came up in my pre, which means they think it will...

KoolAidRelic · 23-06-2011 6:38pm

Geog ariphic wrote: »

While i try to figure that out - do you mean multiply above and below by 1/(k/k), or multiply both sides by it?

Edit:Ok right its a different way of multiplying by k above and below, gotcha.
If that's your definition of a perfectly normal integral, i hate to see what u consider difficult

Yeah, it's the same as mutiplying by k/k, but just to make it clearer that you don't have a k on the top line. Once you get to that stage though it's a normal one.

The ones I hate are the 1/(a^2 - x^2)

Geog ariphic · 23-06-2011 6:50pm

jamesr1775 wrote: »

is projectiles tht bounce likely this year?

em sorry again, followed all ur instuctions, its working out well just can't get to the second last line on the marking scheme, i have:

(1/((kg)^(1/2)))*invtan((3kg)^(1/2)) = pi/3

jamesr1775 · 23-06-2011 6:52pm

KoolAidRelic wrote: »

Yeah, it's the same as mutiplying by k/k, but just to make it clearer that you don't have a k on the top line. Once you get to that stage though it's a normal one.

The ones I hate are the 1/(a^2 - x^2)

the one i hate is find the area of a disc WITHOUT THE ****ING HINT!!!
lol sry still pissed about tht

KoolAidRelic · 23-06-2011 7:11pm

Geog ariphic wrote: »

em sorry again, followed all ur instuctions, its working out well just can't get to the second last line on the marking scheme, i have:

(1/((kg)^(1/2)))*invtan((3kg)^(1/2)) = pi/3

I think you just did your factoring wrong, should be arctan(sqrt(3)).
Here's how I did it: http://i51.tinypic.com/2a813jm.png

aranciata · 23-06-2011 7:47pm

for the part B of the collisions question... it's usually the i value that's ever involved in the calculations, right?

larkin1993 · 23-06-2011 9:17pm

aranciata wrote: »

for the part B of the collisions question... it's usually the i value that's ever involved in the calculations, right?

yeah

Geog ariphic · 23-06-2011 9:41pm

KoolAidRelic wrote: »

I think you just did your factoring wrong, should be arctan(sqrt(3)).
Here's how I did it: http://i51.tinypic.com/2a813jm.png

I see where i went wrong, i got it. You're a legend, thank you.

Ps you should have a minus up the very top, which then cancels with the one on ur third line, but we won't fight over it ;P

KoolAidRelic · 23-06-2011 10:22pm

Geog ariphic wrote: »

I see where i went wrong, i got it. You're a legend, thank you.

Ps you should have a minus up the very top, which then cancels with the one on ur third line, but we won't fight over it ;P

Ah so I should! I was wondering why in my written out ones I had -pi/3 on the other side. It disappears when you square anyway so it doesn't matter.

yannfann · 23-06-2011 10:40pm

The next hour and a half will see me cram more than I have in the entire year. Cmooooon b2!!!!!! Anyone else not need It for points and tempted to not show up? Or am I the only idiot here? :P

LilMissCiara · 23-06-2011 10:43pm

yannfann wrote: »

The next hour and a half will see me cram more than I have in the entire year. Cmooooon b2!!!!!! Anyone else not need It for points and tempted to not show up? Or am I the only idiot here? :P

Cramming in projectiles before bed (bed will be around 1.30) and then getting up at 6 to do Pullys and Wedges (I have NEVER done a wedge questions..

)...

yannfann · 23-06-2011 10:45pm

LilMissCiara wrote: »

Cramming in projectiles before bed (bed will be around 1.30) and then getting up at 6 to do Pullys and Wedges (I have NEVER done a wedge questions.. )...

Hardest part with them I'd the first 10 things you write down at the start! Just triple check the accelerations and reactions and you'll fly through the rest!

LilMissCiara · 23-06-2011 10:47pm

yannfann wrote: »

Hardest part with them I'd the first 10 things you write down at the start! Just triple check the accelerations and reactions and you'll fly through the rest!

Huh..?! :O

I'm guessing you just mean forces?

yannfann · 23-06-2011 10:56pm

LilMissCiara wrote: »

Huh..?! :O

I'm guessing you just mean forces?

Yeah but I tend to make a mess of the reaction forces in particular! But yeah I'm pretty much talking about the forces.

LilMissCiara · 23-06-2011 11:01pm

yannfann wrote: »

Yeah but I tend to make a mess of the reaction forces in particular! But yeah I'm pretty much talking about the forces.

K, cool.. They're ok though, T, F, R and W?

yannfann · 23-06-2011 11:02pm

LilMissCiara wrote: »

K, cool.. They're ok though, T, F, R and W?

Yeah I really can make a hames out of any small thing if I don't triple check it :P
You'll be grand anyway!

LilMissCiara · 23-06-2011 11:05pm

yannfann wrote: »

Yeah I really can make a hames out of any small thing if I don't triple check it :P
You'll be grand anyway!

I'm just hoping that it's a nice paper with no wedges! :L I have a good grasp on Part As, I know the concepts for Part Bs but generally manage to f up!

aranciata · 23-06-2011 11:35pm

ACK THE 2010 PAPER WAS SO EASY! what if we get one as difficult as the 2001 paper??

Maybe_Memories · 23-06-2011 11:39pm

Looking forward to seeing this paper myself.
Solutions will be up for this as well

aranciata · 23-06-2011 11:58pm

How do i do terminal velocity if it comes up in Q10? Do I just fill in 0 for v?

* Applied Maths * predictions / discussion / aftermath (1 thread only please)

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