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# OCR Physics A G484 Jan 2012 - The Newtonian World Watch

1. (Original post by shorty.loves.angels)
I've not sat it before. I'm 23 and want an A level in physics so that I have more chance of getting onto teacher training for science... so I'm self teaching the whole course. Today was my first exam

3 to go and a few practicals!
Oh right

Ouch. Self teaching physics CANNOT be fun, especially the theoretical stuff. Makes my head spin
2. (Original post by wibletg)
Oh right

Ouch. Self teaching physics CANNOT be fun, especially the theoretical stuff. Makes my head spin
Actually, it's brilliant. Moving at your own pace and finding resources that work for you is SO much better, and you have way more motivation/ don't get bored. I did crap at A level maths (all those years ago) because I understood none of the context and had no idea where to go to study in my own way. Now, I've HAD to go out and learn for myself and it's way better.

Also, physics has put so much A level maths into context that I'm considering re-sitting maths.
3. For anyone who's interested

% UMS. . . 100 80 70 60 50 40 30
Jun 11 Raw 52 44 40 36 33 30 27
Jan 11 Raw 53 45 41 37 33 29 25
Jun 10 Raw 56 48 44 40 36 33 30
Jan 10 Raw 53 45 41 37 34 31 28
4. (Original post by aquark)
For anyone who's interested

% UMS. . . 100 80 70 60 50 40 30
Jun 11 Raw 52 44 40 36 33 30 27
Jan 11 Raw 53 45 41 37 33 29 25
Jun 10 Raw 56 48 44 40 36 33 30
Jan 10 Raw 53 45 41 37 34 31 28
Niiiiiiice.

Bit of room for a slip up there
5. Except that with only 14 marks between A and E last year. Thats about 3 marks per grade.

a 3 mark slip-up can be a awhole grade.

The A grade is low 44/60 = 73%
The E grade is high 30/60 = 50%

Its a good paper if you are an A/B student - its not so good if you are a CDE student.

UMS marks get stretched at the top and squashed at the bottom.
6. I have a question:
For the standard SHM graphs (x/v/a), in the book it shows that at T=0s, x=0m and v=Vmax. (2πfA). It also states that at T=0s, KE=0 and PE=max.
Why is this? Surely at max velocity, kinetic energy should be max (as k.e.=0.5mv^2). Similarly, at x=0m, potential energy should be 0 (as gpe=mgh).
Any help would be much appreciated!
7. (Original post by teachercol)
Except that with only 14 marks between A and E last year. Thats about 3 marks per grade.

a 3 mark slip-up can be a awhole grade.

The A grade is low 44/60 = 73%
The E grade is high 30/60 = 50%

Its a good paper if you are an A/B student - its not so good if you are a CDE student.

UMS marks get stretched at the top and squashed at the bottom.
Hmm, never really considered that, bit unfair for them then unless most people pick up enough marks to at least get an E then struggle beyond that?

How do these things work?
8. (Original post by sweetascandy)
I have a question:
For the standard SHM graphs (x/v/a), in the book it shows that at T=0s, x=0m and v=Vmax. (2πfA). It also states that at T=0s, KE=0 and PE=max.
Why is this? Surely at max velocity, kinetic energy should be max (as k.e.=0.5mv^2). Similarly, at x=0m, potential energy should be 0 (as gpe=mgh).
Any help would be much appreciated!
Which book is this and I'll have a look, from what you say I agree with you
9. (Original post by wibletg)
Which book is this and I'll have a look, from what you say I agree with you
The graphs on page 46 and 48 (both are labelled Figure1) from this book.
10. (Original post by sweetascandy)
The graphs on page 46 and 48 (both are labelled Figure1) from this book.
Hmm. I've had a look in my copy and there's nothing on SHM on page 46 and 48

But I'd agree, at the equilibrium position v = max and therefore ke= max.
11. Just wondering if anyone could list all the experiments we need to know. I know the brownian motion, SHC of liquid/solid but what others are there we need to know?
12. What uncertainties are there un the SHC (Solid) experiment
13. (Original post by zonka)
What uncertainties are there un the SHC (Solid) experiment
Heat loss - leads to a lower value of delta t if you've used a known time therefore as c is proportional to one over delta t if delta t is smaller then c is larger
14. (Original post by zonka)
Just wondering if anyone could list all the experiments we need to know. I know the brownian motion, SHC of liquid/solid but what others are there we need to know?
I've done the brownian motion experiment, but never seen a question/ answer for it. Have you got a link to the key points they're after?
15. Does anyone have a complete list of all the things we need to memorize (Such as experiments, assumptions of ideal gas theory etc.)
16. DOes anybody know how many sf we are supposed to use or if it even matters ? thanks 4 ur help
17. (Original post by High VOLTAGE)
DOes anybody know how many sf we are supposed to use or if it even matters ? thanks 4 ur help
I usually judge it by how many are given in the question. It also depends on how much difference it would make to the answer. Practising should clue you up though
18. (Original post by shorty.loves.angels)
I usually judge it by how many are given in the question. It also depends on how much difference it would make to the answer. Practising should clue you up though
Usually 3 sigfig isn't it?
19. (Original post by wibletg)
Usually 3 sigfig isn't it?
Yeah if that's easier to follow then fair enough I've never really heard it explicitly stated as that so I've just got used to what is expected.

And I suppose the question doesn't always contain the same units you're going to calculate
20. Hey guys, the weekend before the storm is approaching, goodluck in your revision and the eventual exam!

Im focusing mostly on the "Thermal Physics" and "Ideal Gases" chapter. I don't study chemistry so I find some of the molar qualatative questions more difficult, whereas the circular motion and gravitational chapters come more natrually to me. One thing that confuses me somewhat is not mixing up the assumptions made as a result of Brownian Motion and the Kinectic Model of Gases.

Updated: April 16, 2012
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