Multiple Choice Answers (2 Viewers)

[SnowTau]

After a discussion with my teacher afterwards, I believe these are the correct answers, feel free to correct me.

(I don't know about you but I was able to take my multiple choice booklet, so you can check them)

1. D
2. A or B (Unsure of this one)
3. C
4. D
5. C
6. A
7. A
8. B
9. B
10. C

 

[ben_carroll93]

I got a for the first one because i figured the smaller cylinder would more further if the big cylinder moved a little bit

 

[SnowTau]

I got a for the first one because i figured the smaller cylinder would more further if the big cylinder moved a little bit

Yes, that's correct, however it says you are moving cylinder Y (the bigger one) 1mm, X HAS to move more than 1mm, using what you just said...
And to do it correctly you have to find the area of each cylinder

pi cancels, so,
360^2/120^2 = 9.
So for each mm the bigger one moves, the little one moves 9, hence D.

 

[ben_carroll93]

what was the answer then?

Yes, that's correct, however it says you are moving cylinder Y (the bigger one) 1mm, X HAS to move more than 1mm, using what you just said...
And to do it correctly you have to find the area of each cylinder

pi cancels, so,
360^2/120^2 = 9.
So for each mm the bigger one moves, the little one moves 9, hence D.

 

[SnowTau]

D), 9mm.

 

[ben_carroll93]

ahh k. yeh i got 9mm but I swear it was 'a' lol

 

[xblacksheepx]

i agree completely with those answers, with 2 being b, not a

 

[ben_carroll93]

i'm fair sure the answer to 2 was 'a'. Its a form of inter granular corrosion between the constituents of brass which is zinc (anode) and the copper (cathode) when placed in an electrolyte the two form a galvanic cell and it starts to corrode. You don't need an electrolyte for stress cracking corrosion or whatever it was.

 

[SnowTau]

I'd never heard of stress corrosion cracking so went with a

The multiple choice was pretty easy actually... in the trial almost no one got over 50% for the multiple choice at my school.

 

[ben_carroll93]

yeh haha. I hate it when they buck in random one's like the as1100 one with the tolerance. I had a guess

 

[SnowTau]

yeh haha. I hate it when they buck in random one's like the as1100 one with the tolerance. I had a guess

My teacher never taught us that or mentioned the whole tolerance thing, but he said c was right almost immediately, he was pretty sure, so I think I got lucky with my pick haha.

 

[ben_carroll93]

yeh i think i put that. it was all under the line i think

 

[SnowTau]

All above

I wasn't sure whether it was above or below, so flicked through the exam to find a drawing with dimensions and it was all above, legitimate "cheating" ftw!

Clarification:

^I just google imaged that but apparently it's from this website haha

http://www.boredofstudies.org/wiki/Focus_Area:_Graphics_Industries

 

[xblacksheepx]

its b, not a, the brass was cold rolled, and that will cause the corrosion, not the salt water.

 

[ben_carroll93]

feck haha. Had a 50% chance haha. That stuff's not even in the textbook. Thats what really shits me with this subject

 

[ben_carroll93]

its b, not a, the brass was cold rolled, and that will cause the corrosion, not the salt water.

why would they have the object in salt water then?

 

[SnowTau]

why would they have the object in salt water then?

To throw you off. Clearly it's worked on some of us if the answer is B haha.

 

[ben_carroll93]

true that haha those bastards

 

[xblacksheepx]

the salt water does make it corrode faster, but the answer couldn't be an electrolytic reaction, for the minority that actually knew what stress corrosion cracking was (not me), salt water just makes it much easier for this to happen.

 

[tie-coon]

Q10 got me. Man I hate true lengths. can never figure them out, I put A as a guess.