AQA AS Further Maths (New Spec) - Paper 2 - 17 May 2018 [Exam Discussion]

Original post by scarlhannan

I did mechanics and discrete
Anyone else that did mechanics, did you feel like in the question on dimensional analysis where it asked you to show what the units of I were, the units of I that they gave were incorrect? Me and few friends think it might have been

\mathrm{The \ dimensions \ of \ I \ were \ correct \ I \ believe \ }[br][E]=ML^2T^{-2}[br][\omega]^2=T^{-2}[br]ML^2T^{-2}=[i]T^{-2}[br][i]=ML^2[br]

Reply 6

Original post by churchofsagan

Agreed, Maths and Stats felt alright to me. One question about statistics the integral resources say to combine categories for Chi Squared tests if the expected frequency is below 5 but the textbook doesn't mention it. Did anyone else combine 2 and 3 or more?

Yes most people in my college did

Reply 7

Original post by churchofsagan

Agreed, Maths and Stats felt alright to me. One question about statistics the integral resources say to combine categories for Chi Squared tests if the expected frequency is below 5 but the textbook doesn't mention it. Did anyone else combine 2 and 3 or more?

Yes, I combined them. It mentions it very briefly somewhere in the textbook.

Reply 8

psycholeo

OP

9

Wait..damn I didn't group in the Chi-Squared question so I hope that's not true..also I got really stuck on the last question on discrete.

Reply 9

Original post by DarthYoda

\mathrm{The \ dimensions \ of \ I \ were \ correct \ I \ believe \ }[br][E]=ML^2T^{-2}[br][\omega]^2=T^{-2}[br]ML^2T^{-2}=[i]T^{-2}[br][i]=ML^2[br]

The question said show that the dimensions on I where ML^2 it’s wasnt wrong

Reply 10

scarlhannan

8

Original post by DarthYoda

\mathrm{The \ dimensions \ of \ I \ were \ correct \ I \ believe \ } [br][E]=ML^2T^{-2} [br][\omega]^2=T^{-2} [br]ML^2T^{-2}=[i]T^{-2} [br][i]=ML^2 [br]

ah okay, must have been me getting confused then

Reply 11

Ditch a good paper, I did mechanics and stats and it was soooo much better than the pure.

Reply 12

Original post by psycholeo

Stats was alright I didn't know how to do the probability function though. I did discrete which was harder than stats

The probability function was different. We've never had to do that sort of thing before. Making it a piecewise function also made it more difficult.

You had to realise the area was 1 and then do a triangle's area to calculate f(1.75)
Then you can use that to calculate the two separate equations for the line as you now know two coordinate pairs for each.

Reply 13

Original post by scarlhannan

ah okay, must have been me getting confused then

Maybe you used radians/degrees as a dimension, I think someone from my college might have done that?
I still find it weird that angles are dimensionless but there's a proof somewhere.

(edited 5 years ago)

Reply 14

psycholeo

OP

9

Original post by DarthYoda

The probability function was different. We've never had to do that sort of thing before. Making it a piecewise function also made it more difficult.

You had to realise the area was 1 and then do a triangle's area to calculate f(1.75)
Then you can use that to calculate the two separate equations for the line as you now know two coordinate pairs for each.

I could remember that, but I just got confused because I wondered how i'd have set it up.

Reply 15

Original post by psycholeo

I could remember that, but I just got confused because I wondered how i'd have set it up.

I think having had the pure on the Monday made it quite stressful and it made doing the exam difficult.

Reply 16

churchofsagan

4

Original post by DarthYoda

Yes, I combined them. It mentions it very briefly somewhere in the textbook.

Awesome, must have missed it in my slightly panicked skim through the textbook.

Reply 17

scarlhannan

8

Original post by DarthYoda

Maybe you used radians/degrees as a dimension, I think someone from my college might have done that?
I still find it weird that angles are dimensionless but there's a proof somewhere.

the LHS of the equation was kinetic energy right?
so I did ML²T^-2 = [LT^-1]²
I thought of angular velocity just as velocity, not thinking about the fact that it was angle, not length
I reckon quite a few people could have made the same mistake I did, easy to not spot

Reply 18