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# AQA GCSE Physics Unit 2 and 3 (20th May) watch

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1. cool :P
I also fought unit 3 was a lot more difficulter than unit 2 what where your thoughts?
(Original post by PawanAviator)
great!
2. (Original post by Nelson Barnaby)
okee i put friction but just checking what others fought
for critical angle, did ur line go along surface of glass?
3. (Original post by Turtlebunny)
Here are some of the answers I got for some questions in P2 and P3, that I am pretty sure are correct:

P2: Conservation of momentum calcs - 5m/s
P2: Half life of the element was 12 years.
P2: Advantages of fusionable fuels: Don't produce radioactive waste that needs to be disposed off (something to that effect), and they produce more energy per Kg - some more could've been said probably - they're hydrogen isotopes, so are renewable and abundant.
P2:51 coulombs for the charge question , and 612Joules for energy transferred
P2: Rocket velocity Q: The graph was B.
P2: rocket velocity increases ?? I mean bit of a vague question, but oh well. Difference between speed & velocity - velocity has a direction, speed does not.
P3: First Q, was 1.25
P3: Refractive index, first glass question was 1.5 something
P3: Second q: 26.18 degrees or 26.2
P3: hydraulics Q: 84000N
P3: bus won't topple as line of action is within the base, and doesn't produce a resulting moment
P3: eye: ciliary muscles & retina - also the critical angle one, the line went straight forward when i = critical angle
P3: 20,000hz for ultrasound, and wavelength = an atom, although i put electron, after I crossed out an atom lol - weird question.
P3: No of coils 18...
P3: Motor effect, and the arrow you had to draw was one going upward toward the top of the page.
P3: Centripetal force: D - could've said, mass of car, radius of circle it is travelling in, or distance from the centre, or speed. - also in this instance it is friction which causes it.
That's all I can remember atm, but all in all, a pretty good paper set by AQA for both P2 and P3. Hope you all did well guys.
P2: Plum pudding is positive
P3: Conditions was short sight - the 60 year olds had a focal length/power or whatever it was of 0.5 metres - you also had to estimate the diopters which was anywhere between 0.6-0.8 probably.
P2: The gravitational and kinetic energy was 3.6 J i think, or was that the braking distance Q idk
weirdly , i put the velcoty decreases for the rocket. i changed it because it will run out of thrust leaving gravity to decelerate it right? it will also reach terminal velocity?
for critical angle, did ur line go along surface of glass?

i dont think so :O

do u mean the one where we had to draw the light where it comes out of the semi circle?
5. for the '20 000Hz' question about ultrasound, didnt' it ask for the minimum?
(Original post by PawanAviator)
weirdly , i put the velcoty decreases for the rocket. i changed it because it will run out of thrust leaving gravity to decelerate it right? it will also reach terminal velocity?
6. (Original post by Nelson Barnaby)
cool :P
I also fought unit 3 was a lot more difficulter than unit 2 what where your thoughts?
yeah , i messed up on the momentum question for unit 2.

i put 12000/2400 = 5m/s.
then wrote 20m/s in the answer.

i have no idea why. hope i get the 2 marks still..
.
7. (Original post by Nelson Barnaby)
for the '20 000Hz' question about ultrasound, didnt' it ask for the minimum?
yep it did. that is the minimum value.
8. (Original post by PawanAviator)
yeah , i messed up on the momentum question for unit 2.

i put 12000/2400 = 5m/s.
then wrote 20m/s in the answer.

i have no idea why. hope i get the 2 marks still..
.
damn!! I got 5m/s for that one
think i messed up a few others though :'(
Oh well, i think i can still get an a*
9. (Original post by PawanAviator)
yep it did. that is the minimum value.
oh oops i fought ultrasound was 20hz
10. (Original post by Nelson Barnaby)
oh oops i fought ultrasound was 20hz
haha , i thought that at first , but then changed my mind. thats the range of the hearing of a human ear. its alright man. Its only a mark.

i messed up on the x-ray wavelength one though.
11. why is half life 12 not 8?
you halve 40 twice to get to 10. so surely halve 36 twice to get 9?
people getting mixed up with dividing by 3 i think because they used 80, not 40g lol,
12. Spoiler:
Show
yeh i got that one wrong too also i said diameter of a tennis ball
13. I'm so confused about the half life one, everyone is saying different answers and I'm almost positive it's 9.

Can't remember the whole question, but whatever you did with the 80, you had to do the opposite to the 36 (in the end I ended up /2/2).. Can't remember the whole question otherwise I'd go through what I did, but what the hell is the answer?!
14. (Original post by cornishparty)
I'm so confused about the half life one, everyone is saying different answers and I'm almost positive it's 9.

Can't remember the whole question, but whatever you did with the 80, you had to do the opposite to the 36 (in the end I ended up /2/2).. Can't remember the whole question otherwise I'd go through what I did, but what the hell is the answer?!
12. 80 i halved to 40 in first half life. 40 is then halved to 20 and 20 down to 10. That is 3 jumps. the sum of the 3y = 36 therefore y = 12.
15. (Original post by Nelson Barnaby)
why is half life 12 not 8?
you halve 40 twice to get to 10. so surely halve 36 twice to get 9?
people getting mixed up with dividing by 3 i think because they used 80, not 40g lol,
16. (Original post by PawanAviator)
haha , i thought that at first , but then changed my mind. thats the range of the hearing of a human ear. its alright man. Its only a mark.

i messed up on the x-ray wavelength one though.
i dont remember that question. was it on the higher paper or foundation?
17. (Original post by Nelson Barnaby)
i dont think so :O

do u mean the one where we had to draw the light where it comes out of the semi circle?
I think thats the one he's/she's talking about. if they are i think they are right because at the critical angle the refracted ray just goes along the boundary
18. Hey guys was the terminal increasing or decreasing?
19. (Original post by JSinha)
i dont remember that question. was it on the higher paper or foundation?
most likely both
20. Also for the 6 marker I did not add any information of the period table or anything. I just said the relative mass for the sub atomic particles and the charge. I also said protons and neutrons are in the nucleus. That was all. I only filled around half the page. 5/6?
Was there anything I missed?

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