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

zuluin · 24-06-2011 1:41pm

i think u had to take negative a as they said deceleration. thats what i found out when i ended up with a negative answer . so i had to go back over and do q-10 again.

KoolAndDaGang · 24-06-2011 1:47pm

Could have been worse I suppose, but certainly did not get an A.

Dublad93 · 24-06-2011 1:50pm

That was fairly woeful...

Anyone get for q1 (a t = 7/8
(b t1+ t2 = t ???

q2 (a ii 49.6m??

q4 (a 3g/4?

q7 (a ii 21/100?

KoolAndDaGang · 24-06-2011 1:51pm

I remember getting 7 over 8 for 1a, if that helps.

Dublad93 · 24-06-2011 1:53pm

KoolAndDaGang wrote: »

I remember getting 7 over 8 for 1a, if that helps.

haha sound...quite possibly one of the very few things i got right

KoolAndDaGang · 24-06-2011 1:55pm

Haha I was just going to say that myself. . disappointing

red_red_wine · 24-06-2011 1:55pm

I can't vouch for these answers being correct, but these are the answers I got:

1 (a) t = 7/8
(b) t = t1 + t2
Least time = 5t/3

2 (a ) -i + 8j
(ii) 49.61 m

(b) 28.96 < theta < 60

3. (a) (I) x=50
(II) tan inverse 3

(b) (I) tan inverse 3/2
(II) e = 1/(sqrt 2)

4 (a) a = 5.023

(b) I didn't write down my values for the various tensions, because for some reason I got a negative tension?

6 (a) Omega = 4, a = 2.6, E = 0.395

(b) Omega = Sqrt (g/2)

10 (a) y = 2e^3.5

(b) (I) s = 200ln1.25

(II) 19.24

MedMan101 · 24-06-2011 1:59pm

anybody want to confirm some answers for me?

Q1 a) 7/8
b) ii) t iii)2t

Q2) a) i) -i-8j
ii) 49.614m

28.96<Q<60. I got dis wrong, i piked d wrong angle by accident. dere was a choice of 60 and 13.174 nd i sed 13.173<Q<28.96. how stupid! :mad:

Q3) a) i) 50
ii) 71.565
b) i) 56.31
ii) 1/(root)2

Q4) a) 2.153ms-2
b) tensions: 120g/49, 219g/98, 365g/49

Q5) a) i) (1+6e)>0
ii) e>1/4
b) i) K= (1+e)/2
ii) e= 3/4

Q10) a) y=66.231
b) i) 44.629m
ii) 0.336 ms-1

All in all, a lovely test!
and i must say, Q5 was rediculously easy....took no more than 10 min!

lufc1993 · 24-06-2011 2:11pm

red_red_wine wrote: »

I can't vouch for these answers being correct, but these are the answers I got:

1 (a) t = 7/8
(b) t = t1 + t2
Least time = 5t/3

2 (a ) -i + 8j
(ii) 49.61 m

(b) 28.96 < theta < 60

3. (a) (I) x=50
(II) tan inverse 3

(b) (I) tan inverse 3/2
(II) e = 1/(sqrt 2)

4 (a) a = 5.023

(b) I didn't write down my values for the various tensions, because for some reason I got a negative tension?

6 (a) Omega = 4, a = 2.6, E = 0.395

(b) Omega = Sqrt (g/2)

10 (a) y = 2e^3.5

(b) (I) s = 200ln1.25

(II) 19.24

didnt take down answers but 2,3,4,6 all look familiar

lufc1993 · 24-06-2011 2:14pm

**** forgot to say 28.96<theta<60 just wrote down answers

Brian123M · 24-06-2011 3:01pm

Q1 a 7/8
b ii t1 + t2 = t
iii 2/3 t (thats wrong)

Q2 b 29 < x < 60

Q3 a ii 74
b i 68.2
ii root34/root35 or something similar to that

Q5 a ii e > 3/8
b i e+1 / 2

Q8 forgot the answers

Q10 a 2e^7/2

Geog ariphic · 24-06-2011 3:03pm

Though i'm the only one likely to ever post on this again (bar teachers), i'd just like to send out a huge apology to everyone who read my earlier post, about doing question 7.
It was shocking. Bloody awful. For a topic called 'statics' there was a good bit of motion involved. Hooke's law, i don't know if that's on the Applied maths course, but it was needed. I spent so long on that i barely got onto part b,

but the angles were so odd that i know alot of trigonometry was involved, and would have taken ages. I threw down some equation using what i though some of the angles were (90 minus alpha all over the place), hoping to get some marks.

Integration was lovely! Not sure about the very end, i just put total distance over total time to get the average, but the rest was fine.
Thanks so much to ye here, got me thinking about manipulating fractions in a way that made today's very easy.

Got all the tensions in connected particles, that was really easy?

never got a value between 0 and 1 for e in nay question though, generally large than 10 though once i had -0.336??

lufc1993 wrote:

forgot to say 28.96<theta<60 just wrote down answers

The first looks very familiar, not sure if i got 28 point something or 26 point something. The second angle though, i got 41 point something. Oh well.

ride-the-spiral · 24-06-2011 3:13pm

I quite liked Q7. Part a was grand once you knew to apply hooke's law. And for part be, you could replace any sin(90-theta) with cos(theta).

deiseguuy93 · 24-06-2011 3:13pm

how could anyone be happy with that exam?

Geog ariphic · 24-06-2011 3:20pm

ride-the-spiral wrote: »

I quite liked Q7. Part a was grand once you knew to apply hooke's law. And for part be, you could replace any sin(90-theta) with cos(theta).

I knew you could that, from maths, but i don't know if saying 90 - theta was right in the first place, just took a guess cos time was up.

Is hooke's even on the syllabus? i mean i do physics so fair enuf but there are some ppl who dont.

we've never done anything with elastic string in app maths and its like 2 pages in physics, so im probably screwed for it. There were probably a few different values for acceleration you needed right?

I woulda done projectiles but i saw the bounce (as predicted) and just said no. i cant do the bounce DX

Alcohol_MAN · 24-06-2011 3:22pm

Okay what can we say about the tensions?
heres my answer for queation 4 b

Light pulley string> 225N
5kg pulley> 58. something N (negative though) :?
2kg > 44.1 N

anyone wanna correct me?

also though i did well

1) a)7/8
b) couldn't do

3)
a) 50
b) (WTF??)

5
a) 1/4 < e < 1

6)
b) (20g)^1/2

10 a) y=2
b) t= 6. something
average = 7. something :S

if anyone can comfirm or correct these it would be much appreciated

Phareon · 24-06-2011 3:39pm

Im kind of pleased 'cos I tried!! But I've kind of been neglecting Applied Maths all year, cos it was my eighth subject!! I knew that I could have done everything if I had studied, or gone over it at all, but I'm not really bothered since everything else went great!!
I got answers for everything, but I might have bluffed my way through some questions and made stuff up!! Anyway, it wasn't as bad as I thought it'd be!! Here's hoping it goes well!
/rant.

knjmooney · 24-06-2011 3:40pm

Alcohol_MAN wrote: »

Okay what can we say about the tensions?
heres my answer for queation 4 b

Light pulley string> 225N
5kg pulley> 58. something N (negative though) :?
2kg > 44.1 N

anyone wanna correct me?

also though i did well

1) a)7/8
b) couldn't do

3)
a) 50
b) (WTF??)

5
a) 1/4 < e < 1

6)
b) (20g)^1/2

10 a) y=2
b) t= 6. something
average = 7. something :S

if anyone can comfirm or correct these it would be much appreciated

1 a) and 5 a) look good, I can't confirm 6 but everything else doesn't look great.... sorry

anna_k · 24-06-2011 3:43pm

that was pretty tough....strangely i think my pre (the deb one) was better :mad:
I don't really care now though...it was only an extra subject...and I'm so glad the leaving is over!!!!!

Geog ariphic · 24-06-2011 3:59pm

anna_k wrote: »

that was pretty tough....strangely i think my pre (the deb one) was better :mad:
I don't really care now though...it was only an extra subject...and I'm so glad the leaving is over!!!!!

Do i know you? Name looks familiar..

ride-the-spiral · 24-06-2011 4:02pm

Geog ariphic wrote: »

I knew you could that, from maths, but i don't know if saying 90 - theta was right in the first place, just took a guess cos time was up.

Is hooke's even on the syllabus? i mean i do physics so fair enuf but there are some ppl who dont.

we've never done anything with elastic string in app maths and its like 2 pages in physics, so im probably screwed for it. There were probably a few different values for acceleration you needed right?

I woulda done projectiles but i saw the bounce (as predicted) and just said no. i cant do the bounce DX

It is on the syllabus, it composes of half of Q6 (Sometimes the full question)
In that particular question you had to calculate the extension (prove that it was 7cm) and then after that it's a normal statics question, except instead of tension in the string supporting the particle, it's the restoring force of the spring.

You're expected to cover the whole course, even if you only do six questions. I know the majority of people can leave out hydrostatics without worrying about it coming up in other sections, but SHM and circular motion are pretty closely linked to statics anyway.

KoolAidRelic · 24-06-2011 4:07pm

Geog ariphic wrote: »

Is hooke's even on the syllabus? i mean i do physics so fair enuf but there are some ppl who dont.

we've never done anything with elastic string in app maths and its like 2 pages in physics, so im probably screwed for it. There were probably a few different values for acceleration you needed right?

I woulda done projectiles but i saw the bounce (as predicted) and just said no. i cant do the bounce DX

Hooke's law is definitely on the syllabus, yeah. It comes up semi-often in SHM. That question on the paper is VERY like ones I've done before (almost identical, in fact to some) and didn't involve much thinking. Part (i) was using trigonometry (you had the length of a side and the tan of the angle).

Part (ii) was just equating tension to -ks.

Geog ariphic · 24-06-2011 4:11pm

KoolAidRelic wrote: »

Hooke's law is definitely on the syllabus, yeah. It comes up semi-often in SHM. That question on the paper is VERY like ones I've done before (almost identical, in fact to some) and didn't involve much thinking. Part (i) was using trigonometry (you had the length of a side and the tan of the angle).

Part (ii) was just equating tension to -ks.

Very like one in SHM, or statics? we've never done SHM...
I hate my half-assed teacher. We had two classes a week at 8.10 for two years.

Alcohol_MAN · 24-06-2011 4:11pm

I just realized i F-ed ten in the A!!!!

Brian123M · 24-06-2011 4:21pm

Did any1 else do question 8 ?

KoolAidRelic · 24-06-2011 4:23pm

Geog ariphic wrote: »

Very like one in SHM, or statics? we've never done SHM...
I hate my half-assed teacher. We had two classes a week at 8.10 for two years.

I can't remember - I just remember looking at the question and thinking I'd done one so very like it that it took no time at all. I got it done in less than five minutes cause I was on autopilot. Barely finished (and not sure if right) the b part... but I did start it with fifteen minutes left as an extra question.

We only ever had one class a week from four until six... Long class, but enjoyable cause we had the best teacher

ride-the-spiral · 24-06-2011 4:26pm

Brian123M wrote: »

Did any1 else do question 8 ?

I did. Was a nice enough question.

Brian123M · 24-06-2011 4:30pm

What answer did u get for angular velocity and the length of a simple pendulum ?

anna_k · 24-06-2011 4:34pm

Geog ariphic wrote: »

Do i know you? Name looks familiar..

probably...im a really popular person.
no really...you possibly do although I can't say your name looks familiar:D

mr_brightside · 24-06-2011 4:46pm

Does anyone know is there such thing as attempt marks, or is it the five or nothing? Is it in any way like the maths where one stupid slip only costs you a mark if all the actual maths bits are right?

Though Q6 was unreal, seemed a bit too good to be honest.. any one get omega = 7 ? And then 10 a i think i made a balls of, should it have worked out really evenly or was it sort of awkward?

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

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