[DOWNLOAD] My Half-Yearly Examination (3 Viewers)

[Fizzy_Cyst]

Here is my Healf-Yearly Examination for my 2013 classes.

They sat the examination today, overall feedback has been that MC was hard, calculations were hard, but theory was pretty good, which is kinda how I aimed it.

Space and Motors and Generators (Upto Generators)

View attachment MF - Half-Yearly Examination.pdf

Marking scheme will be constructed once I have read through a few responses and have decided how I want to mark it

 

[Fizzy_Cyst]

If anyone has had an attempt at the MC. Please post your answers on here, or PM them to me.

I will buy a car for the first person who gets them all correct as even my top students (I am expecting mid-b6) only got 6 or 7 correct.

 

[hayabusaboston]

Srs? U buy a car? dude u must be kidding? u r kidding right?

 

[Obvious]

Srs? U buy a car? dude u must be kidding? u r kidding right?

 

[hayabusaboston]

Bro idk ok, I cant tell if he's exaggerating just to convey how difficult he thinks the MC questions are, or if he legit will buy a car for first person to get 11/11.

 

[Fizzy_Cyst]

Bro idk ok, I cant tell if he's exaggerating just to convey how difficult he thinks the MC questions are, or if he legit will buy a car for first person to get 11/11.

If you don't have a go at answering, you will never find out!

*Teachers don't lie.






*disclaimer: teachers do lie, surprisingly well too.

 

[espiritulol]

Looking through the exam now, bumping for Professor Trollface in q9 haha

 

[someth1ng]

Looking through the exam now, bumping for Professor Trollface in q9 haha

It's even more funny because it's a true troll question (A).

 

[bleakarcher]

It's even more funny because it's a true troll question (A).

lol, I thought it was 0 and was wtf'ing.

 

[anomalousdecay]

Did it in 19 minutes and 16 seconds. Doubting I got more than 7. I guessed question 4 and question 6.

1) B
2) C
3) A
4) B
5) C
6) D
7) C
8) B
9) D
10) B
11) C

 

[hayabusaboston]

Did it in 19 minutes and 16 seconds. Doubting I got more than 7. I guessed question 4 and question 6.

1) B
2) C
3) A
4) B
5) C
6) D
7) C
8) B
9) B
10) B
11) C

Brah I did it in 4 minutes and 2 seconds and 16 milliseconds and 19 microseconds and 22 nanoseconds and 8 picoseconds and 1 femtosecond and 3 attoseconds and 49 zeptoseconds and 5 yoctoseconds. U mirin brah???

 

[anomalousdecay]

Brah I did it in 4 minutes and 2 seconds and 16 milliseconds and 19 microseconds and 22 nanoseconds and 8 picoseconds and 1 femtosecond and 3 attoseconds and 49 zeptoseconds and 5 yoctoseconds. U mirin brah???

Sure, I am. What do you use to measure yoctoseconds...........................

 

[Hypem]

Tried it:

1. B
2. C
3. A
4. No idea, I'll say D
5. C
6. D
7. C
8. Not getting any of the answers, I'll say B
9. 0
10. A
11. C

I probably got 0/11, 1/11 if I'm lucky.

Edit: lol isn't Q9 just 0? It produces a net rotational torque but the forces cancel out right?
http://puu.sh/2GbKE.png

 

[anomalousdecay]

We got different answers for 10 and 11. I guessed 4 aswell :lol.

I tried to solve question 4 by using simultaneous equations, but it didn't work for time for some reason.

 

[Hypem]

lol guessed 10...no idea what to do.

I'd probably say 6 is D though, i thought it said EMF again instead of force

 

[anomalousdecay]

I think for 10 it increases at that instant, but once the current is constantly flowing, then the flux is zero. The wording of a question can completely stuff you up.

 

[Hypem]

How do you work the question out anyway?

 

[anomalousdecay]

Wow, I think Professor Trollface was actually Trolling. It looks like the answer is zero, yeah. But I calculated D, without taking into consideration it was asking for the net force.

 

[anomalousdecay]

How do you work the question out anyway?

T=Fr = nBIAcos(theta) = (1)(2T)(1.5A)(0.1)(0.1)(cos 0) = 0.03Nm

F = T/r = 0.03Nm / 0.05m = 0.6N

Therefore, It is D if it says the force at that particular moment in time.
But it says net force so the answer should be zero.

 

[someth1ng]

1. B (obvious)
2. C (you switch engines off between the stages)
3. C (high altitude=lower g)
4. A (calculated)
5. C (Fc=Fg=Gm1m2/d^2)
6. C (Net EMF=0 for both, back EMF is double for the 20V, net force=0 for both)
7. D (if you consider friction and gravity)
8. B (Dodgy question - not clear enough, I'm assuming area means one loop)
9. A (net force=0)
10. B (Use RH rule, makes flux in the same direction - flux density increases)
11. D (Dodgy question - it's not clear with how everything in connected/measured - I feel that change to split-ring commutator makes it positive, rotating in the opposite direction makes the flux be measured as negative.)