first part i sed theyre in rapid, random motion.

second part i sed they are colliding with the air molecules and so the air molecules must also have random motion. then i mentioned that the speed of the air molecules is greater than that of the smoke particles as they have smaller mass. then i finished off by saying that they are moving

the calculation one i got as 450m/s

Reply 168

Kooper

That was a ridiculous paper - easily harder than jan or june 2010. I was a bit stumped by the air momentum helicopter thing until I saw that it was "this" mass of air, then from there it was OK(ish). What did people get for the tide equation? I got 13 + sin(1.4 x 10E-4 t) (assuming t starts at mid tide as the tide is coming in), but realised after that it should have been 15.5 instead of 13 since that's the eq. position. Also, the kilowatt hour shocked me a bit - never in my life have I seen quite so bold a synoptic question!

Reply 169

yash123A

can someone post the paper up, with the mark scheme? thanks

Reply 170

sc0307

8

i was so stretched for time!

did anyone else get 13.2 for the total energy before and 13.1 for the total energy after??

Reply 171

EmperorMustard

11

Original post by TinySnowflake

Did the question require you to put temperature values on the side?
I thought it said it didn't...

18, 0 and -18 were already there, it said you didn't need to add a scale to the time axis :smile:

Reply 172

EmperorMustard

11

Original post by sc0307

i was so stretched for time!

did anyone else get 13.2 for the total energy before and 13.1 for the total energy after??

I got 13.2 or something for before, and then right down to 3. something after

Reply 173

Oh my Ms. Coffey

Original post by EmperorMustard

I got 13.2 or something for before, and then right down to 3. something after

I got 13.2 down to like 3.2 or something, with momentum as 4/3

Reply 174

FruitsPunchSamurai

Original post by nirvana001

first part i sed theyre in rapid, random motion.

second part i sed they are colliding with the air molecules and so the air molecules must also have random motion. then i mentioned that the speed of the air molecules is greater than that of the smoke particles as they have smaller mass. then i finished off by saying that they are moving

the calculation one i got as 450m/s

I got that as well, but when I was working out temperature in that question, I got a ridiculously large number. 1.5x10^26, I was thinking, "How is that even remotely possible?"

I got 2.5 for the amplitude question.

Reply 175

CapsLocke

11

this paper was a load of b****, seriously, the the helicopter question p**** the hell out of me, I tried every combination of numbers and couldn't get 6000, then realised at the end it said cylinder so didn't have time to do that

kilowatt an hour annoyed me, that's AS! argh

prob going to have to retake ;/ it's on the 27 June aswell dam.

Reply 176

sc0307

8

i got 481ms-1

firstly i used E=3/2 kT for one molecule

then multiplied by avagadros constant for one mole

plugged that into E=1/2mv^2 to get the speed

is this how everyone else done it??

Reply 177

CapsLocke

11

Original post by sc0307

i got 481ms-1

firstly i used E=3/2 kT for one molecule

then multiplied by avagadros constant for one mole

plugged that into E=1/2mv^2 to get the speed

is this how everyone else done it??

I did 1/2mv^2 for hydrogen, used that energy for oxygen, and used 1/2mv^2 again to find v

got 450

Original post by FruitsPunchSamurai

I got that as well, but when I was working out temperature in that question, I got a ridiculously large number. 1.5x10^26, I was thinking, "How is that even remotely possible?"

I got 2.5 for the amplitude question.

really, I'm sure it's 5???

(edited 13 years ago)

Reply 178

sc0307

8

amplitude for the harbour question?

surely it was 18m cos that was the maximum depth?

Reply 179

In the looney bin

Original post by yash123A

what did everyone write about in the brownian motion question

My 3 points (3 marks):

-Random,chaotic motion
-Intermolecular collision
-Proof of kinetic gas theory therefore the molecules exert a pressure.

Original post by sc0307

i was so stretched for time!

did anyone else get 13.2 for the total energy before and 13.1 for the total energy after??

I got 13.2J down to 3.2J,therefore inelastic.

Original post by FruitsPunchSamurai

I got that as well, but when I was working out temperature in that question, I got a ridiculously large number. 1.5x10^26, I was thinking, "How is that even remotely possible?"

I got 2.5 for the amplitude question.

Also got 2.5 for amplitude, good to know :tongue:

Official Thread For OCR Physics A G484 Jan 2011

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