**DCG Before/After**

aaa3

Hi guys,
Just a quick question on Geological Geometry.
Whats the method of finding the strike for a stratum?
Thanks in advance for your help!

Ky Abu

aaa3 wrote: »

Hi guys,
Just a quick question on Geological Geometry.
Whats the method of finding the strike for a stratum?
Thanks in advance for your help!

You have usually your 3 outcrop points on you map. Draw an Elevation of these different points, i.e.

Outcrop at A is 50m
Outcrop at B is 70m
Outcrop at C is 90m

Draw a Level Line/Horizontal Line in Elevation. It can be drawn anywhere, but take it from your middle point, in this case B.

Project down to Plan, and join back to point B. This is the Strike. To find the Dip Angle, Setup an X1, Y1, Perpindicular to the Strike, Measure off your 3 points Altitudes again, 50m, 70m and 90m, they should join in a straight line, if not your after making a mistake! (they will join in a straight line, as the Strike in Plan is a True Length Line on the surface of the stratum of Ore, Whe you look perpindicular to the Strike, you get a Point View of it, and your essentially find the Angle of Inclination of the Stratum to the Horizontal, OR.... The DIP) Continue on the line joining A B and C until it hits your X1, Y1, and Bobs your Uncle..

dorcan

Does anyone know how to clean the t square part where you draw the line with. Without damagen its straigthess

jamo2oo9

Just use a damp cloth and then dry it...? I've used my sleeve of my jumper to clean it for years.

dorcan

jamo2oo9 wrote: »

Just use a damp cloth and then dry it...? I've used my sleeve of my jumper to clean it for years.

Cheers

kingcobra

I take it we can get tracing paper in the exam?

Thataone

kingcobra wrote: »

I take it we can get tracing paper in the exam?

No idea if you can or not but just being nosy here, if you don't mind me asking, what do you use tracing paper for?

Leaving Cert Student

Does one have to specify what method they used for ellipse if it isn't clear?

kingcobra

Thataone wrote: »

No idea if you can or not but just being nosy here, if you don't mind me asking, what do you use tracing paper for?

For dynamic mechanisms when drawing cycloids, and also possibly, but very unlikely, for gears.

kingcobra

Leaving Cert Student wrote: »

Does one have to specify what method they used for ellipse if it isn't clear?

Well as long as you've shown your construction lines you should be ok.

Leaving Cert Student

kingcobra wrote: »

Well as long as you've shown your construction lines you should be ok.

But for the trammerl method there aren't any?

kingcobra

Leaving Cert Student wrote: »

But for the trammerl method there aren't any?

Oh right, then just stick the trammel on to your sheet after you've finished it.

JoeOBrien1

I'm just looking at the marking schemes for the dcg as prep for the exam. I've noticed the marking for the projects, it says stuff like considered all relevant information - excellent presentation = full marks or w/e. I was wondering how i'd be marked if I considered all relevant information but have only good presentation?

Eurovisionmad

Nervous out for this exam, it really is one that if you don't know what you're doing you can't do very much! I'm just hoping perspective doesn't come up as a long question, I barely know it and don't want to be confined to the other two!

jamo2oo9

This is my final exam and honestly, I don't feel worried about it. I found Planes and Lamina the most difficult but now, I actually understand it. I'm hoping for Perspective and Interpenetration. Hopefully the Interpenetration isn't too difficult to draw. Road Geometry and Hyperbolic questions are my choices in Section C. I did really bad in Section A in the mocks mainly down to skew lines and I didn't know how to work it out. Let's hope it will be a nice paper and hope everyone will do well in it.

Good luck!!

Barster

How did people get on? Was pretty happy with it myself tbh with you now , only didnt get the parabola bit on B2 , and Didnt finish the Elevation on the perspective question , think I'll lose many marks?

Anyone any idea what marks ye'd need for an A1?

and how many could you have lost in that test in order to get one? bout 30? :P

Eurovisionmad

You can't lose more than 40 marks for an A1 including the project!

The long questions were grand I think, nothing massively hard in the questions I did, there were a few bits I wasn't sure about but I think overall they went grand! The short questions though were a totally different story! I don't think there was one question I was sure how to do, I knew however what the answers needed to look like in most cases so I just drew lots of lines and arcs and made the drawing look like what o needed to have :L A1 though looking a bit Dodge maybe now hard to know though!

Leaving Cert Student

They were skew lines right? and was the true length for section a q4 as easy as it looked?

Thataone

Thought it was grand enough, did B-2, B-3, C-1, C-3 and all the short Qs.
Both from B were as handy as they come, got them both done within 30 mins each. Map was quite bitty, read the last part of the Q wrong but corrected it, but still think I may have gone wrong somewhere. However, my thinking is that because there was so many parts, it'll be ok. Same for C-2.

Tis all done now anyways!

Thataone

Leaving Cert Student wrote: »

They were skew lines right? and was the true length for section a q4 as easy as it looked?

I said they were skew lines. Thought I did something funny on that Q, had it done in like 2 secs but couldn't think what else to do to it so perhaps it was that straight forward.

jamo2oo9

Yeah, I took it as skew lines alright. How did everyone find the perspective question? And the dimetric question? I think there was a mistake with the measurements for one of the parts because mine was very short in height of the goals. For perspective, the result was rather distorted really with one side fine but the other was very narrow. Was aiming for an A1 but I've reduced it down to B1.

ScummyMan

Thataone wrote: »

I said they were skew lines. Thought I did something funny on that Q, had it done in like 2 secs but couldn't think what else to do to it so perhaps it was that straight forward.

How did you do that question?

Barster

Leaving Cert Student wrote: »

They were skew lines right? and was the true length for section a q4 as easy as it looked?

Yup think so , to prove it I just showed how they were Parrallell, did anybody else do that?

B2) Didnt get the parabola in Q b2? how many marks you reckon that'd be?

B3;

a - Got the Avp finally didnt get to finish elevation
nice q though

B- Skew lines simple ,

C1- Fine , dip bit dodgy , What height did people use for E on the profile?

C3- Absolutely simple so easy was surprised.

Thataone

Man.UnitedLad wrote: »

How did you do that question?

TBH I can't remember what I put down, got them parallel but can't remember if I got another view after that. I just remember flying through the short Qs and saying they were skew lines Sorry I couldn't be more helpful

Barster

Man.UnitedLad wrote: »

How did you do that question?

I just did normal skew lines procedure , and got to where they were parrallel and said they were skew lines because they were parrallell and didnt intersect ,

for second bit just did and auxillary of the line to get the TL

dorcan

Just wondering if anyone got that exam completly finished. No one in our school did i reckon that the exam needs 15mins min extra. Did anyone else see the sly semi circle in the cam question C-4

dizzymenace

in the dimetric with the goals . how did you get the measurement for the bottom of the goals , I thought about every conceivable way and yet couldnt find it . i dont think any of my class did

Thataone

dorcan wrote: »

Just wondering if anyone got that exam completly finished. No one in our school did i reckon that the exam needs 15mins min extra. Did anyone else see the sly semi circle in the cam question C-4

Think just about everyone in my school got it finished, out of about 30 odd students only one didn't (that I know of) but the timing is tight.

bigt132

For the 4th short question, could you just continue each of the lines until they intersect each other in both the plan and elevation and since both points of intersection aren't directly above each other then you can say they don't actually intersect?

ILoveDance

Roads question was LOVELY!! . . wat was with B-2?? cudnt get part (c)