** LC Applied Maths 2014 - Before and after discussion **

c0unterpart wrote: »

didnt like that at all.No chance of an A now but sure.

how the hell do you prove tanA < tan B ?

I said vx>0 at range, so then I ended up getting 1>0 and then TanA< TanB. It made sense when I did it out...

What time will the paper be up?

Wouldn't mind a look for old times sake

Everyone I was talking to said it was a tough paper. I'd say they'll be nice in the marking scheme or else applied maths might lose its huge A1 rate.

To say that was terrible would be an understatement.

Question 1 was alright. The b part was fairly easy, but I couldn't get (ii) as I forgot what to do.

Question 2 was...less alright. The a part was absolutely terrible, to say the least; I can't remember a single time something like that came up. The b part was fine.

Question 3 was ok. The a part was tricky and really time-consuming, while the b part was ok. The (ii) was very tricky, I thought, and I was forced to move on past it due to the time.

Question 4 was...well...I don't like that diagram so didn't do it. It looks very tricky. The b part seems alright.

Question 5 wasn't too bad in terms of maths, but finding the co-efficient of restitution took so long that there was ample room to slip-up, and I ended up making an error in the maths which had a knock on effect.

Question 6 I didn't like. The first part was a tricky way for them to ask to prove Simple Harmonic Motion. I ended up making an error looking at it now though, as I used the "four" instead of "one over four" which was a stupid error. This had a knock on effect on the second part. The b part I didn't like either. The first part was kind of ok, but I only just noticed that I completely misread the (ii) so that went terribly too.

Question ten seemed ok. I'm worried that I thought it went ok.

Overall, I had been expecting an A1; now, I am not.

EDIT: Ok, so under the absolutely worst case scenario, where each part is 25 marks, an i part is 15, and an ii part is ten, and they remove all of the marks for an incorrect answer, I would be down to 235/300. I don't think it'll be marked that harshly, so maybe I got a B1 pushing it which is better than I thought. I'm not hopeful though.

Nimrod 7 wrote: »

Around 5 or 6pm. I could take a picture of some questions when I get home if you want.

Ah it's alright i'll wait around for it. The physics paper looked lovely so I was wondering would this one be a walk in the park as well - apparently not!

jimbob95 wrote: »

Anyone else feel like they will be lucky to pass after feeling beforehand like they would get at least a B?

I haven't heard of anyone yet who liked the paper so don't give up yet. They'll throw attempt marks at us to keep the high A rate.

Well there goes my A

For Q 9
(a) 3200 and 4800 kg/m^3
(b) (i) x = 45.18 cm (or to be exact, x^2 = 100,000/49)
(ii) Tension = 160 N
(iii) Density = 428.157 kg/m^3 ( or 3000/7 kg/m^3)

RedSeven7 wrote: »

For Question 4(a) - the pulley - does anyone know if the acceleration of A and B is the same, or if the acceleration of B a multiple of the acceleration of A or vice versa??

Shanrahan wrote: »

Yeah they should be the same and then force equals mass times acceleration

I think it's all one acceleration a... And I used T for all tensions throughout the string cause it's only one string.

PhysicsKid99 wrote: »

I used a and 2a because A had two strings attached... Oops

I had the accln of B was half that of A because when A moves forward, the length of the string string both gets longer and shorter because of the way it's set up, so B only moves up half the distance that A moves forwards. Don't really know what I was thinking tbh.

That was a tough paper and pretty out there. Still, apart from question 5 (b) I think I got the answers. Questions 2 and 10 were nice, and though 3 had some trig manipulation, it was fairly basic stuff otherwise. To prove tan B > tan a here's how:

(1+2tan*2B) (tan a) = tan B (taking the bottom off the right hand side and multiplying it by the left.

Therefore if 1+2tan*2B is greater than 1 tan B is greater than tan a (because multipling it by more than one means you get a bigger number).

To prove: 1+2tan*2B>1
2tan*2B>0
tan*2B>0
(tanB)*2>0 true because (real)*2 > 0.

Nicke011 wrote: »

Please tell me are you a student or a teacher? ::D

Student.

For 4 part a indeed the acceleration of A is half acceleration B, got that one wrong but the same thing came up in 2008 and checked it just there.

Anyone get the answer to 4 b part ii, I got 2.67 and 17.47 but no idea if it's right.