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# AQA Physics PHYA4 - Thursday 11th June 2015 [Exam Discussion Thread] watch

1. (Original post by GANGA_SLAYER)
Could someone please explain question 3 a part ii from this paper please https://60abffc9b401b1c0936e01291c15...%20Physics.pdf
I just can't understand it
Here is your desired thought process in terms of how AQA like to word questions:
First clue - 'behaves like a spring' automatically F=Kx should spring to mind (see what I did there lol)

Second clue - 'Hooke's law' > just reinforces my initial point about F=Kx.

Now you're given the force (9.81 x 58) and you're also given X the spring constant K. Rearrange and there you have it sir
2. Can any smart person inform me as to why an object feels weightless if it is on a planet rotating with a centripetal force equal to the object's weight?
3. (Original post by NEWT0N)
Well I definitely remember it having something to do with the flux through the secondary coil.

Ah yes, it's coming back: A changing magnetic field is needed in the secondary coil because (by Faraday's law) the rate of change of flux linkage needs to be nonzero to induce an emf in the secondary coil. A direct current will produce a steady field so rate of change of flux linkage = 0 --> no induced emf, which is bad. Great, thanks!
Hey Isaac,

Can you explain the key points which need to be mentioned when answering how a transformer operates, please

Thanks
4. I'm confused as ****, aqa shows the exam as wednesday, my friend says wednesday, i got thursday in the back of my book

AQA A2 Physics unit 4, someone confirm for me pls
5. (Original post by ima fail)
I'm confused as ****, aqa shows the exam as wednesday, my friend says wednesday, i got thursday in the back of my book

AQA A2 Physics unit 4, someone confirm for me pls
Thursday the 11th of june.

He's messing
6. Thursday

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7. ty babes
8. Can someone help me with 4b) iv) on jan 2010 phya4/2 please?
http://www.aqa.org.uk/subjects/scien...d-mark-schemes
9. (Original post by NEWT0N)
Can any smart person inform me as to why an object feels weightless if it is on a planet rotating with a centripetal force equal to the object's weight?
Not entirely sure but this may help

F = mv^2/r F=mg

mg = mv^2/r

g = v^2/r

- could you tell me what question you're talking about plez <3
10. I cannot fxcking believe im asking this - how on earth do you do Q3
http://filestore.aqa.org.uk/subjects...1-QP-JUN14.PDF
11. (Original post by Kennethm)
I cannot fxcking believe im asking this - how on earth do you do Q3
http://filestore.aqa.org.uk/subjects...1-QP-JUN14.PDF
Mass of water = pv
so 1000 x (2x10^-4) = 0.2 kg

Speed = vol/area

7.2x10^-4 / 2x10^-4 = 3.6m/s

Momentum = 0.2 x 3.6
=0.72

IGNORE THIS
Mass of water = pv
so 1000 x (2x10^-4) = 0.2 kg

Speed = vol/area

7.2x10^-4 / 2x10^-4 = 3.6m/s

Momentum = 0.2 x 3.6
=0.72
13. (Original post by Kennethm)
I now feel incredibly stupid. My teacher marked it right too. My school is just terrible haha.

Apologies.
14. (Original post by Master Sam)
Hey Isaac,

Can you explain the key points which need to be mentioned when answering how a transformer operates, please

Thanks
Hey, I know the q wasn't directed to me but this really helped:
http://www.cyberphysics.co.uk/topics...r/trnsfrmr.htm

15. Don't understand this 😂😭😭😭😭😭😂

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Can someone help me with 4b) iv) on jan 2010 phya4/2 please?
http://www.aqa.org.uk/subjects/scien...d-mark-schemes
Hey I think the hardest part of the question is getting round the kWh thing but that's just a unit of Energy (E = Pt). If you convert this unit to make it Kilowatt-seconds, you can just use your previous answer to work out the cost.

Hope this helps.
17. Whip out the coffee lads!! We've got 36 hours to jamjamjam

P.S it sound like I'm a lost soul but I've been through PHY4 thoroughly about 5 days ago but had other exams up until now #TeamPreparedToNotBePrepared
18. (Original post by gcsestuff)

Don't understand this 😂😭😭😭😭😭😂

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I don't think you're looking at the right part of the markscheme for that question
19. (Original post by Kennethm)
Not entirely sure but this may help

F = mv^2/r F=mg

mg = mv^2/r

g = v^2/r

- could you tell me what question you're talking about plez <3
But why does it happen when mv^2/r=mg? >:O
(first post here: http://www.thestudentroom.co.uk/show...47347&page=160 )
20. (Original post by Master Sam)
Hey Isaac,

Can you explain the key points which need to be mentioned when answering how a transformer operates, please

Thanks
Sorry I'm definitely the wrong person to ask I only know the cgp explanation (if you don't have the book I'd be happy to copy it out for you)

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