!! LC Applied Maths 2016 Before and after

DownOneTourist

I'm optimistic about it. Hoping for an a1 but I will be content with a b1 and up

mrBigDiCk

Which questions are everyone doing?
Im covering 1-5 , 7 + 10 hopefully - depends on how much I can cram into 2days!

TSMGUY

mrBigDiCk wrote: »

Which questions are everyone doing?
Im covering 1-5 , 7 + 10 hopefully - depends on how much I can cram into 2days!

with your username I hope you can't cram a lot :pac::pac::pac:

DownOneTourist

I'm doing 1,2,3,4,5,10 maybe 9 also

DublinArnie

1,2,3,4,5 and 10.

7 is an option!

Anyone have decent Rigid Body Notes to share? The proofs are fine but can't wrap my head around the whole inertia thing.

onlinenerd

Doing 1,2,3,4,5 and 10. Hoping for an easy paper since I dont finish till like half 7 on Friday and the last thing I want to do is tear my head on calculus

DownOneTourist

onlinenerd wrote: »

Doing 1,2,3,4,5 and 10. Hoping for an easy paper since I dont finish till like half 7 on Friday

hmm? It's the last exam. you're finished at 4:30pm like the rest of us? No?

onlinenerd

DownOneTourist wrote: »

hmm? It's the last exam. you're finished at 4:30pm like the rest of us? No?

Nope I do applied maths at 5 because I do religion as well

DownOneTourist

onlinenerd wrote: »

Nope I do applied maths at 5 because I do religion as well

But won't you know what's on the paper?

onlinenerd

DownOneTourist wrote: »

But won't you know what's on the paper?

Nah its only like a half hr difference between the exams and I am supervised by the school

saif.khalid14

Does anyone had any 2016 mock paper (deb or exam craft) if so could you please forward it to me thanks

Bazinga_N

Feel like I know nothing for Applied Maths :embarrassed: Really getting stressed about it now!

DownOneTourist

Bazinga_N wrote: »

Feel like I know nothing for Applied Maths :embarrassed: Really getting stressed about it now!

I'm going over 6 q's between today tomorrow and friday morning. Theres still loads of time so just keep at it.

adam240610

Gonna be doing a lot of maths tomorrow now... Better be a good paper haha, could get anywhere from 70-99% depending on the paper.

Misty_01

saif.khalid14 wrote: »

Does anyone had any 2016 mock paper (deb or exam craft) if so could you please forward it to me thanks

If you don't mind, please send it to me too ! Thanks

adam240610

Here's hoping for a good final paper for all of us.

DownOneTourist

adam240610 wrote: »

Here's hoping for a good final paper for all of us.

indeed.
q1 can be difficult so i will do it last
q2 can be difficult. i hate it
q3 is usually ok
q4 is usually ok (No wedges please!!)
q5 easy to set up but there can be difficulty in angles
q10 was very nice last year. keep it up SEC!!

iFergal

Hope this is a nice paper. I have q1-6, 8 and 10 prepped very well, hopefully the 2 options will come in handy if we get a bit of an odd paper! :P

Then finally free for the whopper sesh.

DublinArnie

iFergal wrote: »

Hope this is a nice paper. I have q1-6, 8 and 10 prepped very well, hopefully the 2 options will come in handy if we get a bit of an odd paper! :P

Then finally free for the whopper sesh.

Can you pm any inertia notes please for Q8?

iFergal

DublinArnie wrote: »

Can you pm any inertia notes please for Q8?

Damn, you couldn't have been more unlucky... one of my friends couldn't find his and took them off me a few hours ago because I was finished revising it.

There isn't a whole pile of variance in the question B's, so it might be worthwhile looking for some different questions and having a look at marking schemes. In particular, the older papers with hand-written solutions - they can be difficult to read but have more detail.

Basic concepts would be based around knowing where to set the standard position from where to measure heights for potential energy - this will always be the lowest centre of gravity (careful of point masses) - then gain in kinetic is equal to loss in potential. If they are set up right, they are hard to mess up.

If you need to find period, for the mgh bit underneath the line: turn the system on it's side with the axis at one end and add up all the moments (force [mg] by distance from the axis).

Nice tip to remember is if you have a triangle (of say 3 rods joined together), the centre of gravity will be a third of the height. C.O.G = median = bisector of altitudes. Altitudes bisect each other in the ratio of 2:1, hence h/3.

Anything that is moving, be it down an incline or a pulley system will have regular kinetic energy of course.

DownOneTourist

DublinArnie wrote: »

Can you pm any inertia notes please for Q8?

https://www.youtube.com/watch?v=-Fz3LzbzKrQ&list=PL63819923917D99C0&index=46 this might help but im not sure

DublinArnie

iFergal wrote: »

Damn, you couldn't have been more unlucky... one of my friends couldn't find his and took them off me a few hours ago because I was finished revising it.

There isn't a whole pile of variance in the question B's, so it might be worthwhile looking for some different questions and having a look at marking schemes. In particular, the older papers with hand-written solutions - they can be difficult to read but have more detail.

Basic concepts would be based around knowing where to set the standard position from where to measure heights for potential energy - this will always be the lowest centre of gravity (careful of point masses) - then gain in kinetic is equal to loss in potential. If they are set up right, they are hard to mess up.

If you need to find period, for the mgh bit underneath the line: turn the system on it's side with the axis at one end and add up all the moments (force [mg] by distance from the axis).

Nice tip to remember is if you have a triangle (of say 3 rods joined together), the centre of gravity will be a third of the height. C.O.G = median = bisector of altitudes. Altitudes bisect each other in the ratio of 2:1, hence h/3.

Anything that is moving, be it down an incline or a pulley system will have regular kinetic energy of course.

I can do the compound and simple oscillations and all that, but can't wrap my head around how you obtain the moment of inertia.

I thought I knew how and was doing well for simple questions, but looking at the marking scheme it just confuses me.

For example, the moment of inertia of a square lamina with axis to the perpendicular... In the marking scheme, they did (2)(4/3)ml^2 but that's for a rod no?

With the guaranteed proof it's an easy question to obtain most marks in.

iFergal

DublinArnie wrote: »

I can do the compound and simple oscillations and all that, but can't wrap my head around how you obtain the moment of inertia.

I thought I knew how and was doing well for simple questions, but looking at the marking scheme it just confuses me.

For example, the moment of inertia of a square lamina with axis to the perpendicular... In the marking scheme, they did (2)(4/3)ml^2 but that's for a rod no?

With the guaranteed proof it's an easy question to obtain most marks in.

Moment of inertia of an axis on the plane of the lamina (through it's centre-line) is 1/3ml^2, just like a rod. What you need to do is get one horizontal and vertical along the plane (both 1/3ml^2) and then use the perpendicular axis theorem. Ia + Ib = Ic. So the moment of inertia about an axis perpendicular to it's centre is 1/3ml^2 + 1/3ml^2 = 2/3ml^2. Then you will often be required to move it using the parallel axis theorem to one of the vertices.

DublinArnie

iFergal wrote: »

Moment of inertia of an axis on the plane of the lamina (through it's centre-line) is 1/3ml^2, just like a rod. What you need to do is get one horizontal and vertical along the plane (both 1/3ml^2) and then use the perpendicular axis theorem. Ia + Ib = Ic. So the moment of inertia about an axis perpendicular to it's centre is 1/3ml^2 + 1/3ml^2 = 2/3ml^2. Then you will often be required to move it using the parallel axis theorem to one of the vertices.

Ah that makes sense now. So all lamina use the same moments of inertia as the rod.

Makes sense now! Thanks.

adam240610

DownOneTourist wrote: »

indeed.
q1 can be difficult so i will do it last
q2 can be difficult. i hate it
q3 is usually ok
q4 is usually ok (No wedges please!!)
q5 easy to set up but there can be difficulty in angles
q10 was very nice last year. keep it up SEC!!

I'm gonna try do it in order, how I always do it, might do 10 first if it looks okay.

1-3 are normally pretty easy for me, 4 is grand with no wedges, 5 is good too but they can get quirky. 6 is very easy every few years, otherwise pretty hard. I do 9 and 10 as well, which have both been pretty easy last few years

Would take last years paper any time though

onlinenerd

hoping for nice q2 and q10 and q5b but otherwise hoping for a B

adam240610

onlinenerd wrote: »

hoping for nice q2 and q10 and q5b but otherwise hoping for a B

Hoping for a B1 minimum, that or over and I'll be happy, otherwise i'll be counting english for points I'd say.

DownOneTourist

onlinenerd wrote: »

hoping for nice q2 and q10 and q5b but otherwise hoping for a B

Likewise. If you get less 20/50 in any one question you have lost the A1. If there are two part b's that I find very tough I probably won't get an A1. I'm going to make sure that I'm writing for the whole 2 and half hours though. You get can do any question any amount of times wrong but if you get it right even once or are on track to get it right you will get most of the marks. Also in previous tough app math papers any sort of attempt which is usually 4/10 marks went up to 7/10 while a good attempt which is usually 7/10 went up to 10/10. So try to stay optimistic while you're in there. And stick to your timing!

chris241111

Could someone tell me what 'relative to the ground means' again just having a mini meltdown

DublinArnie

DownOneTourist wrote: »

Likewise. If you get less 20/50 in any one question you have lost the A1. If there are two part b's that I find very tough I probably won't get an A1. I'm going to make sure that I'm writing for the whole 2 and half hours though. You get can do any question any amount of times wrong but if you get it right even once or are on track to get it right you will get most of the marks. Also in previous tough app math papers any sort of attempt which is usually 4/10 marks went up to 7/10 while a good attempt which is usually 7/10 went up to 10/10. So try to stay optimistic while you're in there. And stick to your timing!

Didn't know applied maths even had attempt marks!!!

DownOneTourist

chris241111 wrote: »

Could someone tell me what 'relative to the ground means' again just having a mini meltdown

you are looking directly overhead the cars, aeroplanes or ships.

Appmaths97

Make sure you answer what being asked.
If it asks for velocity, dont leave it in i and j vector. make sure you give the magnitude and direction of the particle.
its an easy 5 marks to lose on a 30 mark question.

DownOneTourist

Appmaths97 wrote: »

Make sure you answer what being asked.
If it asks for velocity, dont leave it in i and j vector. make sure you give the magnitude and direction of the particle.
its an easy 5 marks to lose on a 30 mark question.

and the units!

adam240610

Do the easiest looking question first, could make a huge difference and stop the nerves early on.
If there's a huge mess of algebra left it's only worth 5 marks, move on and come back to it at the end, especially if you're pushed for time, nothing is more important than this tbh.

bookworm20

with oblique collisions if asked for the kinetic energy do you use the speed or just the "i" velocity

adam240610

bookworm20 wrote: »

with oblique collisions if asked for the kinetic energy do you use the speed or just the "i" velocity

1/2(m)(i^2+J^2)

You have to use both for kinetic, because if I is zero, it still has kinetic energy in the J

iFergal

bookworm20 wrote: »

with oblique collisions if asked for the kinetic energy do you use the speed or just the "i" velocity

Just use the i-component as the j-component will be the same and cancel out so unnecessary work. If we happen to get a collision along the j-axis (where the i will stay the same), the opposite - that did come up at least once.

Also, if you have multiple collisions, such as 3 spheres or a wall involved, kinetic energy after will use the final velocities after the collisions have taken place; intermediary velocities are irrelevant - just before and after.

Edit: In my experience it won't make a difference Adam. Hoping I'm correct now. :P

Misty_01

Can any body tell me why the initial velocity in the j sense for this question is 9.8 ?

A ball kicked from a point k on level ground hits the ground for the first time 30 m from k after a time of 2 s. The ball just passed over a wall standing 7.5 m from k.

Thanks

adam240610

iFergal wrote: »

Just use the i-component as the j-component will be the same and cancel out so unnecessary work. If we happen to get a collision along the j-axis (where the i will stay the same), the opposite - that did come up at least once.

Also, if you have multiple collisions, such as 3 spheres or a wall involved, kinetic energy after will use the final velocities after the collisions have taken place; intermediary velocities are irrelevant - just before and after.

Edit: In my experience it won't make a difference Adam. Hoping I'm correct now. :P

It makes it less complex, less likely to make a mistake if you include both :P

iFergal

It actually might be worth pointing out that if it's percentage loss, it'll be over the total kinetic energy (which will be i and j together), so that is an advantage of doing it your way!

I'll still probably stick to just i-components if it's just KE lost in joules though.

bookworm20

also if a question say the "actual" direction of a plane does this mean the direction it is trying go or does this mean the direction the wind is forcing it to go?

adam240610

May this exam not ruin the start to our (late) summers

Also can you rephrase that^ ?

iFergal

bookworm20 wrote: »

also if a question say the "actual" direction of a plane does this mean the direction it is trying go or does this mean the direction the wind is forcing it to go?

I think actual could really have two meanings here - and it should be obvious in the context of the question.

If it's in still air or the direction the plane must go, it is the direction it is trying to go in order to compensate for the wind. But in reality the wind is pulling it onto the course for it's destination, which could be interpreted as it's actual direction the plane is physically moving in. The phrasing and set up of the question should make it obvious what they are looking for.

bookworm20

That exam...was horrendous

DublinArnie

****ed up the exam, blanked out and forgot how to do the questions because of anxiety ffs.

Hoping to scrap a C3 with attempt marks and a few good questions (Q10, Q1).

adam240610

Question 1 and 2 were nasty, did 3-6 and 9-10 instead, was happy with the paper, hoping for an A2.

cgill

I quite liked that paper, I did 1,3,4,5,8,10 there were a few tough bits in part Bs but I thought it went well overall.

DownOneTourist

Q1 I didn't get a nice number for U but V was 15. The total distance was 101 point something for me
h didnt work for me.

Q3 happy with part a. I got point 61 for TB and 30 ish for the velocity of the ball at C
I got K equal to sin2theta+root3(1-cos2theta) so that was bad...

Q4 Happy with part a except I got the speed of P wrong.. I got the speed of q but forgot to half it because of the pulley system
part b again was weird for me. The 5g mass moved up for me as well as the 14g mass

Q5 I got the equations down in both questions. Part a was bad for me but part be was ok i think. I got either 18.4 or 71.6 degrees. I didnt say which it was but i wrote both of them into a diagram on the sheet.

Q9 Lovely part A. I got h equal to 4M over rowd squared i think
part b again was tough for me. I didn't know how resting on the the side of the take affected the rod so I got the moments around B let them equal to each other and got X over L equal to S-1

Q10 I got minus 18 for part a so I called that 18 meters. IDK
Part B was bangers

Bazinga_N

bookworm20 wrote: »

That exam...was horrendous

I completely agree, what a terrible way to end the exams!

iFergal

I did not really like that paper at all. Overall I feel likes it is really hard to know how you got on, especially when there was so few questions with show this is equal to this.

Q1 I got, it was fairly okay, not the easiest though.
Q2 Not nice. :P
Q3 This was fairly okay, it was definitely a weird setup and would have rathered a regular q3 but happy enough.
Q4 This has been worse, but has been easier.
Q5 Very weird... usually this question is very easy, but I'm happy with my answers.
Q6 For once I actually liked this, this can be very hit and miss but I think it went well overall.
Q8 Christ.
Q10 Part B (ii)... yeah...

DownOneTourist: I did too, it said distance though, and s is displacement so the minus is okay and you were correct to give your answer as +18. (Well, that's assuming we were right, but if we both got it...)

Appmaths97

iFergal wrote: »

I did not really like that paper at all. Overall I feel likes it is really hard to know how you got on, especially when there was so few questions with show this is equal to this.

Q1 I got, it was fairly okay, not the easiest though.
Q2 Not nice. :P
Q3 This was fairly okay, it was definitely a weird setup and would have rathered a regular q3 but happy enough.
Q4 This has been worse, but has been easier.
Q5 Very weird... usually this question is very easy, but I'm happy with my answers.
Q6 For once I actually liked this, this can be very hit and miss but I think it went well overall.
Q8 Christ.
Q10 Part B (ii)... yeah...

DownOneTourist: I did too, it said distance though, and s is displacement so the minus is okay and you were correct to give your answer as +18. (Well, that's assuming we were right, but if we both got it...)

i think it changed direction at t=2 so you had to get the displacement from 0 to 2 and the displacement from 2 to 3 to get the total disance.