Leaving Cert Applied Maths Thread

Lucy Peden · 02-02-2018 11:33pm

Account Number wrote: »

Well lads, this question appeared on our mocks, and it seemed to cause a bit of confusion.
Assuming I did it right:
s=ut + 1/2(at^2) ---- 240 = 16t --- t = 15
s=ut + 1/2(at^2) ---- 270 = (19)(15) + 1/2(225a)
Essentially a is a minus answer, and surely this can't be right.Someone care to show me the error of my ways?

I attempted it and got a=-2/15

bpb101 · 02-02-2018 11:47pm

I haven't done applied maths for years and I attempted it. Got 64km/h/h ðŸ˜ðŸ˜‚ðŸ˜‚ðŸ˜‚ðŸ˜‚

bpb101 · 02-02-2018 11:56pm

Right. Done it again and I get a reasonable answer. Just over 1ms/s

bpb101 · 03-02-2018 12:05am

Woops I made a simple mistake.
Maybe the guy doing it done the same. I got a minus answer of -0.138. But this could be right.
The horse could have been catching up but easyed off. But it is misleading.

Lucy Peden · 03-02-2018 12:08am

bpb101 wrote: »

Right. Done it again and I get a reasonable answer. Just over 1ms/s

I found the time at which mojo passes the finish line and worked out the answer from that, he passes 10 metres before starlight and so it work out to be 15 seconds, then I used s=ut + 0.5at^2 and solved for a

ignorance is strength · 03-02-2018 2:16pm

As Lucy said, answer is -0.13 m/s^2, which is got using the method you give. Not sure why you think a negative value is illogical. If you visualise the race on a velocity-time graph, despite a decreasing velocity, "Mojo" remains faster than "Starlight" throughout.

Account Number · 03-02-2018 2:46pm

Thanks, lads -2/15 was the value I got as well, I just thought it wasn't right because the question said Mojo sped up, implying a positive acceleration. I guess I just gave it a bit toooo much thought..:P Thanks anyway

ignorance is strength · 03-02-2018 2:59pm

Account Number wrote: »

Thanks, lads -2/15 was the value I got as well, I just thought it wasn't right because the question said Mojo sped up, implying a positive acceleration. I guess I just gave it a bit toooo much thought..:P Thanks anyway

I hadn't noticed that. I think you're right and it's a mistake in the question.

bpb101 · 03-02-2018 3:12pm

Account Number wrote: »

Thanks, lads -2/15 was the value I got as well, I just thought it wasn't right because the question said Mojo sped up, implying a positive acceleration. I guess I just gave it a bit toooo much thought..:P Thanks anyway

i would say they mixed up mojo and starlight's speeds

ignorance is strength · 03-02-2018 3:38pm

Easily done. Mojo's got some speed on him.

But I imagine it might have happened during the editing stage of the question -- either the figures were retrospectively changed so as to make the acceleration negative, and the verb wasn't changed, or the verb was added by someone not familiar with the answer. It might have read something like, "Mojo catches up with an acceleration...", and that, in the edit, that was seen to be imprecise because Mojo continues the negative acceleration after the overtake. (Obviously just speculation.)

Lucy Peden · 03-02-2018 5:59pm

Did anybody manage to show in the projectile question that the initial speed was 28.6m/s? I ve been trying to get it out but must be missing something

ignorance is strength · 04-02-2018 1:32am

Lucy Peden wrote: »

Did anybody manage to show in the projectile question that the initial speed was 28.6m/s? I ve been trying to get it out but must be missing something

Will you post the question?

Lucy Peden · 04-02-2018 11:47am

ignorance is strength wrote: »

Will you post the question?

The first part of that

Lucy Peden · 04-02-2018 11:48am

Don't think it sent

ignorance is strength · 04-02-2018 2:03pm

I think it’s fairly standard. You’re probably just making a trivial error somewhere.

Sx = ucosAt = 52.8, from which you get t = 57.2/u. And then inputting that value for t into Sy = usinAt - gt^2/2 = 2.4 gives you the answer for u.

The second part is somewhat unclear because in reality the answer ought to be the range of values for x between the two times the ball’s height equals the goalkeeper’s reach. It also assumes that any contact between the keeper and the ball will prevent a goal.

randomuniquser · 12-02-2018 4:57pm

How did everyone find the Applied Math mock ?

I personally didnt think it was too bad but q6 (a) wording was quite difficult to understand.
So I chose to do q5 instead.

q9,q10,q2,q1 were pretty easy but 3 part b and 5 part (b) (i) i found a bit tricky.

Overall the paper was pretty fair I think but I don't think it accurately represents what is going to come up in the LC.

Does anyone else feel the same?

Account Number · 07-05-2018 8:53pm

Anyone care to point out where I'm forgetting to carry the one?:p
2017 Paper Q3 (a)(i) I have up to:
(9gh/2)^1/2sin(a)(3h/(9gh/2)^1/2 cos(a))- g/2 (3h/(9gh/2)^1/2 cos(a))^2 (Sorry that's probably one of the ugliest things ever to read), and I can't seem to get the right answer out of it. I keep ending up with tan^2(a)-12tan(a) +3, which doesn't get me the right answer.The marking scheme subs in u for the speed, but I can't make out where it's coming from

skippy1977 · 08-05-2018 5:15pm

It seems to be right...I used the same method, it might just be the way you are tidying up? Here is what I have if it is any help.

lostatsea · 08-05-2018 9:23pm

skippy1977 wrote: »

It seems to be right...I used the same method, it might just be the way you are tidying up? Here is what I have if it is any help.

Congratulations on your beautifully presented solutions.

Account Number · 05-06-2018 8:03pm

Hello, me again. Quickly trying to cover a final topic, in the run up, and am in the middle of Q8. Anyway came across a q in the Oliver Murphy book, which I can't seem to make sense of.Ex 14B Q7 7(ii) I understand it's a form of potential energy, but I can't work out where the h values are coming from.Sorry this is probably a stupid question, but I can't work it out for the life of me:o and I couldn't find a video from our friend on YouTube on it:o

bpb101 · 05-06-2018 9:25pm

Account Number · 05-06-2018 10:09pm

bpb101 wrote: »

Thanks, much appreciated,

but I meant 14B with the uniform rod PQ

. I have the solution for it, I'm just trying to work out where they're getting the values for h1 and h2 from, in the formula.:o

bpb101 · 07-06-2018 9:23pm

Been so long, i forgot there was parts to the chapters

I have all the solutions worked out, so give us a shout if you want a particular answer or pm me and i can send them to you

Celtron · 20-06-2018 9:39pm

What questions are ye all doing? I've covered 1,2,3,4,5,6 and 10, been told 9 is very doable, should I bother starting it now or would I just be wasting time?

lundrum · 20-06-2018 9:43pm

We're doing 1,2,3,4,5,9 and 10. I'm not sure if there's enough time to start on 9 now but fwiw I think it's among the easiest of the questions we've done most years.

Thr000w · 21-06-2018 12:41pm

We've done 1 through 6 and 10.

lundrum · 22-06-2018 5:09pm

What did everyone think of that? My H1 is down the drain I'd say

Curiouscircus · 22-06-2018 5:21pm

lundrum wrote: »

What did everyone think of that? My H1 is down the drain I'd say

Same, no hope of my H1 after that. V difficult. Ended up running out of time as well.

lundrum · 22-06-2018 5:24pm

Curiouscircus wrote: »

Same, no hope of my H1 after that. V difficult. Ended up running out of time as well.

Which questions did you do? I did 1,3,4,5,9 and 10 and a really pathetic attempt at 2 that was basically just a waste of time

Curiouscircus · 22-06-2018 5:26pm

lundrum wrote: »

Which questions did you do? I did 1,3,4,5,9 and 10 and a really pathetic attempt at 2 that was basically just a waste of time

I did 1,2,3,4,5,10

Oh yeah like I read part b of question 2 completely wrong. Misinterpreted it so badly I don’t even think I got any marks for it
Questions 10 and 3 were nice enough though

lundrum · 22-06-2018 6:13pm

Curiouscircus wrote: »

I did 1,2,3,4,5,10

Oh yeah like I read part b of question 2 completely wrong. Misinterpreted it so badly I don’t even think I got any marks for it
Questions 10 and 3 were nice enough though

Don't remember any of the answers you got by any chance?

Thr000w · 24-06-2018 11:20am

I don't think anyone else thought it was. Difficult question 2, horrible 10 b) is enough to send my H1 down the drain.

japester · 26-06-2018 12:15am

Thr000w wrote: »

I don't think anyone else thought it was. Difficult question 2, horrible 10 b) is enough to send my H1 down the drain.

I'm working my way through the paper at the moment, just Q9 and Q10 to complete now. I'll post up my answers as soon as I have them completed for anyone who may be interesed, but this fine weather, apart from my aging brain, is slowing me down bigtime

My overall impression of the paper is that it wasn't the worst I've seen by any means.

Certainly do not despair about possibly losing your H1 since I'm sure the marking scheme sometimes gets altered, especially if a significant percentage of students have difficulty with a particular part of a question etc. Remember the percentage of H1s is typically one of the highest for the Applied Maths subject and I can't see a major decline this year either - this is mainly a consequence of some of the best and brightest taking on the challenge of the subject and the marking scheme is usually fairly generous also if you have a look at them online - you'll certainly get attempt marks for anything that is leading to the correct solution and often many of the marks are weighted towards just coming up with the correct equations of motion involved etc

lundrum · 27-06-2018 1:21pm

If anyone wants to torture themselves, someone’s done out the solutions here http://appliedmathematics.ie/index.php/students/exam-solutions
Can’t speak to their accuracy though. A bit disappointed with 9 if his solution’s correct because I was almost sure I’d got it right

japester · 27-06-2018 2:24pm

lundrum wrote: »

If anyone wants to torture themselves, someone’s done out the solutions here http://appliedmathematics.ie/index.php/students/exam-solutions
Can’t speak to their accuracy though. A bit disappointed with 9 if his solution’s correct because I was almost sure I’d got it right

Hi lundrum, I've been working through the paper also and I've got the first 9 questions completed now. I just took a look at Dominick's solutions for Q9 and I can verify that I got the exact same answers as him for (a) and (b). But do not worry as you could have made a very minor slip and, as we all know, a minor slip in an Applied Maths question can have a "snowball" effect

doctorXwho · 16-08-2018 5:02pm

How did people do?
I missed out on my H1 but got a H2 which I’m happy enough with because I thought the exam didn’t go my way at all on the day

UnknownEntity · 16-08-2018 7:05pm

doctorXwho wrote:

How did people do? I missed out on my H1 but got a H2 which Iâ€™m happy enough with because I thought the exam didnâ€™t go my way at all on the day

I got a H1

lundrum · 16-08-2018 7:09pm

I somehow got a H1 despite knowing for a fact that I got at most 2 questions fully right. All hail the marking scheme.

Account Number · 16-08-2018 10:26pm

A H3, which given I've only been doing it one year was enough for me

(even if it did mean I couldn't even count it). Kicking myself for not taking it at the start of 5th year:P

Ae86VroomVroom · 17-08-2018 2:05pm

Got the H1 also but I thought the exam was fair from the start. I hope you are all happy with your results!

doctorXwho · 17-08-2018 9:42pm

Well done guys!

sirboby · 05-09-2018 10:19pm

Alright whos up for taking applied math this year? I'm self teaching in only one year so god help me.

Ah well im up for the challenge

Peregrine · 05-09-2018 11:41pm

sirboby wrote: »

Alright whos up for taking applied math this year? I'm self teaching in only one year so god help me.

Ah well im up for the challenge

Lots of people have done that. It's definitely possible. Good luck.

Jacobc · 13-10-2019 8:36pm

Hi, I'm looking for solutions to the applied mathematics, I just started 5th year and I'm stuck on Chapter 2 questions mainly at the moment, particularly 2E.
Thanks,
a struggling 5th year.

*Leaving Cert Applied Maths Thread*

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Leaving Cert Applied Maths Thread