# Multiple Choice Answers (1 Viewer)

#### SnowTau

##### Member
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

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#### ben_carroll93

##### New Member
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

##### Member
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

##### New Member
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.

D), 9mm.

#### ben_carroll93

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

#### xblacksheepx

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

#### ben_carroll93

##### New Member
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

##### Member
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

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

#### SnowTau

##### Member
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

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

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#### xblacksheepx

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

#### ben_carroll93

##### New Member
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

##### New Member
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

##### Member
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

##### New Member
true that haha those bastards

#### xblacksheepx

##### New Member
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

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