The Student Room Group

The Physics PHYA2 thread! 5th June 2013

Scroll to see replies

Reply 1900
Original post by jonny7bell
Exactly what I did, and considering they didn't actually give you the wavelength, I would be pissed off if I lost the marks.


i thought i was the only one! thats what i thought surely its the same thing right?
Reply 1901
On the angle with the first question, did anyone get 10 degrees? Would that be accepted? Thanks.
Original post by .raiden.
When its finalised let me know which page its on so I can quote it in the op :smile:


Its on page 80, and if I'm honest, I think that's about as far as its ever going to go.

Post 1599 I believe; http://www.thestudentroom.co.uk/showthread.php?t=2306278&page=80&x=-561&y=-6726#post42984570
Reply 1903
Original post by HenryD
Hello, hmm:
2C) You'll get marks for that yes, you may even get full marks if you explained why t will be the same? If not then 1 or 2 marks (probably 2 if you explained).
5A) Depending on how you wrote it you may get the mark for that, sounds a little ambigious but if the examiner understands you you'll get the mark. 1-2/2
6A) Someone else on here did the same, it's possible that they'll give you that if they're lenient. Probably a 50 50 toss up between whether you get the marks or not. :smile:


thanks so much bro! also you know for the graph on the steel ball through oil? i drew the graph but i didnt dram a straight line at when the ball hits the bottom? would i still get 3marks ?
Original post by HenryD
Hello, hmm:
2C) You'll get marks for that yes, you may even get full marks if you explained why t will be the same? If not then 1 or 2 marks (probably 2 if you explained).
5A) Depending on how you wrote it you may get the mark for that, sounds a little ambigious but if the examiner understands you you'll get the mark. 1-2/2
6A) Someone else on here did the same, it's possible that they'll give you that if they're lenient. Probably a 50 50 toss up between whether you get the marks or not. :smile:


How many marks would this get out of six for the six marker?

Inital quick acceleration shown by steep gradient
As it falls a drag force is produced
As the object falls the drag force on it increases reducing the resultant force
F=ma with respect to Newton's second law and so the acceleration decreases as it falls as shown by the gradient getting smaller
Eventually drag is equal and opposite to weight
Ball travels at constant Velocity shown by the straight part of the graph near the end of time
Reference to Newton's first law as it moves at a constant velocity as there is no resultant force
Some of the energy of the object is converted into internal energy of the oil
It finally hits the bottom as shown by the vertical line at the end



Also for the graph I did this

image.jpg

How many marks would this get out of 3? I thought it's velocity would decrease when it hits the oil then increase again? The final bit was a straight vertical line
Reply 1905
For the efficiency question of the glider, instead of using P=energy/time I did P=FxV and V= distance/time, I got 21% for the answer rounded up. Will that be accepted???


Posted from TSR Mobile
Reply 1906
I got caught out on the waves. Thank God the 6 marker was alright. :smile:
Reply 1907
Original post by gandanmo
thanks so much bro! also you know for the graph on the steel ball through oil? i drew the graph but i didnt dram a straight line at when the ball hits the bottom? would i still get 3marks ?

I'm not sure on that one. I'm thinking the three marks will be for, 1 a straight line up to the first dotted line, 2 a sharp curve downwards after that line, 3 a straight line at the end of that curve. So I think you'll probably be ok but I can't be 100%.
And you're welcome :smile:
Original post by Aarongreatbanks
How many marks would this get out of six for the six marker?

Inital quick acceleration shown by steep gradient
As it falls a drag force is produced
As the object falls the drag force on it increases reducing the resultant force
F=ma with respect to Newton's second law and so the acceleration decreases as it falls as shown by the gradient getting smaller
Eventually drag is equal and opposite to weight
Ball travels at constant Velocity shown by the straight part of the graph near the end of time
Reference to Newton's first law as it moves at a constant velocity as there is no resultant force
Some of the energy of the object is converted into internal energy of the oil
It finally hits the bottom as shown by the vertical line at the end



Also for the graph I did this

image.jpg

How many marks would this get out of 3? I thought it's velocity would decrease when it hits the oil then increase again? The final bit was a straight vertical line

The six marker looks pretty good to me, hard to tell with them cause you can lose marks for your writing and communication etc but I wouldn't be surprised if you got 5 or 6.
That oil graph question was nasty. It depends on whether you think it'll carry on accelerating in the oil or not. But you'll definitely get a mark for the straight line at the start and the flat line at the end. So at least 2/3 and possibly 3/3, difficult to tell.
Original post by Rapidzx
On the angle with the first question, did anyone get 10 degrees? Would that be accepted? Thanks.


I got tan(x)=1/6 so x=9.2. That is what most people seemed to get, so you will probably lose 1 mark for accuracy. What was your method?
Original post by gandanmo
i thought i was the only one! thats what i thought surely its the same thing right?


Well it logically should be, but physics exams tend to be very specific a lot of times which is kind of irritating. So we will probably get the marks, but it isn't guaranteed.
Reply 1910
Original post by .raiden.
It was 2, we managed to find which question wasn't an extra mark :smile:


Oh okay that's good :smile: Is it all up to date now in the original post?
Original post by trentjoseph007
it was other way round mate.


Go back and read the question, it tells you it is transverse and it told you it was a SEISMIC wave.

It didn't tell you it was a secondary seismic wave (s wave) so that would have been what the question was asking for.
What UMS do you think 62 will be?
Original post by HenryD
I'm not sure on that one. I'm thinking the three marks will be for, 1 a straight line up to the first dotted line, 2 a sharp curve downwards after that line, 3 a straight line at the end of that curve. So I think you'll probably be ok but I can't be 100%.
And you're welcome :smile:

The six marker looks pretty good to me, hard to tell with them cause you can lose marks for your writing and communication etc but I wouldn't be surprised if you got 5 or 6.
That oil graph question was nasty. It depends on whether you think it'll carry on accelerating in the oil or not. But you'll definitely get a mark for the straight line at the start and the flat line at the end. So at least 2/3 and possibly 3/3, difficult to tell.


It would accelerate in the oil and the acceleration would decrease (leading to a curve on this portion of the graph similar to the start of the question) until it reached 0 where the graph would be a straight line at a constant maximum velocity.
Original post by Rapidzx
On the angle with the first question, did anyone get 10 degrees? Would that be accepted? Thanks.


I got 10.4 as I used the value given, rather than the value calculated in the first part. I think the marks would still be given...maybe.
Reply 1915
Original post by HenryD
I'm not sure on that one. I'm thinking the three marks will be for, 1 a straight line up to the first dotted line, 2 a sharp curve downwards after that line, 3 a straight line at the end of that curve. So I think you'll probably be ok but I can't be 100%.
And you're welcome :smile:

oh bro one other thing you know for the unloading graph in Q4 i drew a curve coming back down but ending towards the right of the original(loading) but because its a curve do i lose both marks or would i still get one mark for the line ending at the right point on the x-axis> THANKS!!
[QUOTE="gandanmo;42989452"]
Original post by HenryD

oh bro one other thing you know for the unloading graph in Q4 i drew a curve coming back down but ending towards the right of the original(loading) but because its a curve do i lose both marks or would i still get one mark for the line ending at the right point on the x-axis> THANKS!!


I know this wasn't directed at me but on a past paper I did --

- 1 mark for a straight line ending behind the loading line
- 1 mark for it being parallel to the loading line.

Whether it will be the same again I don't know though :smile:
I got caught out on that question about the white light :unimpressed:
Apart from that question the paper was too sexy :awesome:

Posted from TSR Mobile
Original post by g.k.galloway
I got 10.4 as I used the value given, rather than the value calculated in the first part. I think the marks would still be given...maybe.


I did this also, for good reason. Having seen countless mark schemes now, I know that questions where you are asked to 'show that something equals something' allow two answers, generally - one coming from the exact, calculated value from the 'show that' question, or the rough value given in the question. I worked it out both ways, and I believe I got 9.6o or 10.4o, and went with 10.4.

See similar mark schemes if you'd like to be reassured!
Any one got the paper?

Quick Reply