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

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    (Original post by CD223)
    Just wanna say thanks to everyone for making this such a lively and buzzing thread since the beginning. It's definitely helped me prepare and I hope it has for everyone else!

    Let's all smash this paper!


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    Agreed! *crowd roars*
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    (Original post by a.a.k)
    Emf=Blv
    Emf=emf zero*sin( 2*pi*f*t)

    These are not in the data sheet.

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    The second is implied because Emf0 is BANw and w = 2pif

    The first can be derived from the data sheet:
    emf= N* BA/t

    Rectangular object passing through a field:
    Area/ time = length* width/time
    width/ time = speed
    so N BA/t = N BL(w/t) = NBlv
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    (Original post by oonic0rn)
    http://filestore.aqa.org.uk/subjects...1-QP-JAN13.PDF

    question 12 anyone pleeeeeeeeeease?
    Is it 3.6? B? ill explain if im right
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    Can someone please explain this question - the answer is T/2 but I thought the acceleration was in the same direction at this time?
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    Just my predictions here, nothing confirmed


    I think the paper will be on momentum, circles, electric fields, capacitance and transformers (6 marks)
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    Will there be an unofficial mark scheme here tomorrow? And what about MC?
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    (Original post by HenryHein)
    The second is implied because Emf0 is BANw and w = 2pif

    The first can be derived from the data sheet:
    emf= N* BA/t

    Rectangular object passing through a field:
    Area/ time = length* width/time
    width/ time = speed
    so N BA/t = N BL(w/t) = NBlv
    I wasnt expecting an explanation i just wanted to share.
    Thnx anyways.


    Anyother formual not in data sheet plz share


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    (Original post by Dante991)
    Is it 3.6? B? ill explain if im right
    Oh sorry no I meant 6, C
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    (Original post by Dante991)
    Is it 3.6? B? ill explain if im right
    yes it is!!
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    (Original post by huniibehi)
    This is the hardest momentum question I've seen, any ideas??

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    I got the answer to be A, do you know what the right answer is?
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    Any 6 marker predictions? Im thinking Transformers
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    (Original post by aprocrastinator)
    Can someone please explain this question - the answer is T/2 but I thought the acceleration was in the same direction at this time?
    for SHM (the left one), acceleration always acts towards equilibrium and for circular motion, acceleration acts towards the centre (centripetal acceleration). At the initial time therefore, acceleration for the mass-spring system is downwards and the particle in circular motion is upwards because there's where the centre is. After half an oscillation, the particle in circular motion will be at the top and the mass on the spring will be at the bottom so opposite accelerations. Hope this helps
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    (Original post by Dante991)
    Oh sorry no I meant 6, C
    The answer is 3.6


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    (Original post by JuniorDinosaur)
    Any 6 marker predictions? Im thinking Transformers
    A transformers movie joke would be perfect here:ahee:

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    (Original post by JuniorDinosaur)
    Any 6 marker predictions? Im thinking Transformers
    With you on that one. Nice 6 marker too!
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    (Original post by oonic0rn)
    yes it is!!
    Ok basically I did not calculations. But I did some research and this is useful to know.

    Earths radius is 3.7 times bigger than the moons.
    Earths mass is 81 times bigger than the moons.

    This has helped here and then
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    (Original post by CD223)
    Some have got me feeling like David Moyes' time as Utd manager.


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    Some of them even get me like Boeteng when Messi is running at him
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    MORE USEFUL FACTS TO KNOW.

    1) We know the Earth goes round the Sun, all the way around is 2 radians (360 degrees). We also know that it takes a year (approx 365 days) which is therefore about 3.2x107 secs. Therefore = 2 / 3.2x107 = 2.0x10-7 rad/s. We have calculated the angular velocity.

    2) With a mean orbital velocity of 1.023 km/s, the Moon moves relative to the stars each hour by an amount roughly equal to its angular diameter, or by about 0.5°

    3) The ratio of the Sun's radius to the Earth's radius is 1,392,000/12756 = 109.1

    4) The mass of the sun is 1.989 x 1030 kilograms, about 333,000 times the mass of the Earth.

    Hopefully this may save us some calculation stress
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    (Original post by oonic0rn)
    http://filestore.aqa.org.uk/subjects...1-QP-JAN13.PDF

    question 12 anyone pleeeeeeeeeease?
    Field Strength = GM/r^2

    Earth's Mass = 4/3 Pi r^3 * density of the Earth
    Moon's Mass = 4/3 Pi r^3 * 0.6 *density of the Earth

    Rearrange to get r
    Divide one equation by the other

    Hope that helps
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    (Original post by MsFahima)
    Will there be an unofficial mark scheme here tomorrow? And what about MC?
    I will try to write down as many answers as I can after the exam. The MC will be hard to.

    Do you know if you can get a hold of a copy of the MC paper?

    Failing that does anyone know if they can? It'll mean we can make a proper mark scheme.


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