Join TSR now and get all your revision questions answeredSign up now

AQA A2 Mathematics MM2B Mechanics 2 - Monday 22nd June 2015 [Exam Discussion Thread] Watch

    Offline

    2
    ReputationRep:
    (Original post by CD223)
    I've not come across these. Gonna do my first past paper for M2 today. Do you mind elaborating what you mean by it involving quadratics? do you use F=kx^2?
    For example, you may be asked to find the distance x travelled by a particle as it comes to rest while it will be attached to a string. These questions are generally 6 + marks. You would've probably been asked to calculate the elastic potential energy and the extension in earlier parts of the question. You would have to use the law of the conservation of energy. I find these questions so hard..
    • Thread Starter
    Offline

    3
    ReputationRep:
    (Original post by Tiwa)
    For example, you may be asked to find the distance x travelled by a particle as it comes to rest while it will be attached to a string. These questions are generally 6 + marks. You would've probably been asked to calculate the elastic potential energy and the extension in earlier parts of the question. You would have to use the law of the conservation of energy. I find these questions so hard..
    Ew that sounds horrid!
    Forgive my ignorance, Hooke's law and elasticity is the only remaining M2 topic I have left. Did June 2009 and January 2010 just now, skipping those Hooke's law questions which I'll revisit when we've covered them - they don't look nice!
    • Thread Starter
    Offline

    3
    ReputationRep:
    Does anyone have access to a topic by topic set of questions for this exam?


    Posted from TSR Mobile
    • Thread Starter
    Offline

    3
    ReputationRep:
    Can someone please explain to me how part B and C is done? I can do the volume, but I've always been taught to find the mass per unit area, rather than per unit volume. I don't understand how they get the extra x in the solution to B either.

    Please help!



    Attached Images
      
    • Thread Starter
    Offline

    3
    ReputationRep:
    Also, since when was it possible to express acceleration as v(dv/dx)? I've always considered it to be dv/dt? Could someone explain how this actually works out mathematically?



    Attached Images
      
    Offline

    2
    ReputationRep:
    (Original post by CD223)
    x
    To find the distance of the center of mass of the solid from the y-axis we can use the fact that when working with a uniform object it is possible to work with the areas instead of masses, because the area is proportional to the mass.

    so
     2\pi\bar{x}=\pi\displaystyle\int  ^2_0x(2-x)\ dx
    The extra  x comes from the fact that when working out C of M, its the mass in this case volume multiplied by the distance in this case  x

    for part C tan(\alpha)=\frac{\bar{x}}{\bar{  y}} where alpha is the angle to the vertical
    From part b you've worked out that  \bar{x}=\frac{2}{3} and  \bar{y} is the radius of the circle. To work this out it's when  x=0 and you end up with y=\sqrt{2} and bish bash bosh  \alpha =25.2^{\circ}
    Offline

    3
    ReputationRep:
    (Original post by CD223)
    Also, since when was it possible to express acceleration as v(dv/dx)? I've always considered it to be dv/dt? Could someone explain how this actually works out mathematically?


    Use chain rule.
    v\dfrac{dv}{dx} = \dfrac{dx}{dt}\dfrac{dv}{dx} = \dfrac{dv}{dt} = a

    This is a result that you need to use when the acceleration is in terms of x.
    • Thread Starter
    Offline

    3
    ReputationRep:
    (Original post by morgan8002)
    Use chain rule.
    v\dfrac{dv}{dx} = \dfrac{dx}{dt}\dfrac{dv}{dx} = \dfrac{dv}{dt} = a

    This is a result that you need to use when the acceleration is in terms of x.
    Thank you! Never thought of it like that!


    Posted from TSR Mobile
    • Thread Starter
    Offline

    3
    ReputationRep:
    (Original post by Shadez)
    To find the distance of the center of mass of the solid from the y-axis we can use the fact that when working with a uniform object it is possible to work with the areas instead of masses, because the area is proportional to the mass.

    so
     2\pi\bar{x}=\pi\displaystyle\int  ^2_0x(2-x)\ dx
    The extra  x comes from the fact that when working out C of M, its the mass in this case volume multiplied by the distance in this case  x

    for part C tan(\alpha)=\frac{\bar{x}}{\bar{  y}} where alpha is the angle to the vertical
    From part b you've worked out that  \bar{x}=\frac{2}{3} and  \bar{y} is the radius of the circle. To work this out it's when  x=0 and you end up with y=\sqrt{2} and bish bash bosh  \alpha =25.2^{\circ}
    Thank you!


    Posted from TSR Mobile
    • Thread Starter
    Offline

    3
    ReputationRep:
    What would people say is the hardest paper they've come across for this unit?


    Posted from TSR Mobile
    Offline

    10
    ReputationRep:
    (Original post by CD223)
    What would people say is the hardest paper they've come across for this unit?


    Posted from TSR Mobile
    I've been working through them in order mostly, so I haven't come across a particularly hard paper yet to be honest! Generally it's the most recent ones that are worse.
    • Thread Starter
    Offline

    3
    ReputationRep:
    (Original post by Lau14)
    I've been working through them in order mostly, so I haven't come across a particularly hard paper yet to be honest! Generally it's the most recent ones that are worse.
    Oh nice! Is that "in order" from 2005? I started at June 2005 and I'm currently on January 2008. I got set June 2009 and Jan 2010 as Easter homework, so I've done a fair few of the older papers, but not the newer ones :/

    Dread to think how hard it gets around 2013!


    Posted from TSR Mobile
    Offline

    10
    ReputationRep:
    (Original post by CD223)
    Oh nice! Is that "in order" from 2005? I started at June 2005 and I'm currently on January 2008. I got set June 2009 and Jan 2010 as Easter homework, so I've done a fair few of the older papers, but not the newer ones :/

    Dread to think how hard it gets around 2013!


    Posted from TSR Mobile
    From 2006 because 2005 aren't in the past papers college print for us (probably because the first few papers of a spec are usually pretty weird or too easy and there's enough for maths that we can skip some), done up to the end of 2008 plus jan 11 because we were set it for homework and a mock that our teacher put together. Aiming to have done all the papers by the exam, which I should manage easily because it's my last one!
    • Thread Starter
    Offline

    3
    ReputationRep:
    (Original post by Lau14)
    From 2006 because 2005 aren't in the past papers college print for us (probably because the first few papers of a spec are usually pretty weird or too easy and there's enough for maths that we can skip some), done up to the end of 2008 plus jan 11 because we were set it for homework and a mock that our teacher put together. Aiming to have done all the papers by the exam, which I should manage easily because it's my last one!
    Ooh nice! Me too! Apart from the fact that it's my penultimate exam :/ computing on the 23rd June!


    Posted from TSR Mobile
    Offline

    2
    ReputationRep:
    Kinda struggling with vertical circular motion and Hooke's law/ Power. Does anyone have any tips and know where i can find questions to work on?
    • Thread Starter
    Offline

    3
    ReputationRep:
    (Original post by Tiwa)
    Kinda struggling with vertical circular motion and Hooke's law/ Power. Does anyone have any tips and know where i can find questions to work on?
    http://www.physicsandmathstutor.com/...s/m2-by-topic/

    This website should help a lot.

    Feel free to post any questions you're struggling with. I've not covered Hooke's law yet but any vertical circular motion and power questions, feel free to ask


    Posted from TSR Mobile
    Offline

    1
    ReputationRep:
    (Original post by CD223)
    Can someone please explain to me how part B and C is done? I can do the volume, but I've always been taught to find the mass per unit area, rather than per unit volume. I don't understand how they get the extra x in the solution to B either.

    Please help!



    Which paper is this from? Is it from an AQA paper?
    • Thread Starter
    Offline

    3
    ReputationRep:
    (Original post by andywells)
    Which paper is this from? Is it from an AQA paper?
    I believe it was one of the 2005 AQA papers


    Posted from TSR Mobile
    Offline

    2
    ReputationRep:
    (Original post by CD223)
    What would people say is the hardest paper they've come across for this unit?


    Posted from TSR Mobile
    June 2014 (unfortunately, as it'll be most similar to ours). They just included loads of left of centre questions worth quite a few marks, and the grade boundaries were relatively high too. I sometimes rush so I made quite a few RTFQ mistakes as the question wasn't as I'd assumed it was. Managed to scrape a B.
    • Thread Starter
    Offline

    3
    ReputationRep:
    (Original post by sarcastic-sal)
    June 2014 (unfortunately, as it'll be most similar to ours). They just included loads of left of centre questions worth quite a few marks, and the grade boundaries were relatively high too. I sometimes rush so I made quite a few RTFQ mistakes as the question wasn't as I'd assumed it was. Managed to scrape a B.
    Without giving too much away, what made it hard? Was it just not as guided as previous papers in breaking down step by step what to do for each question?


    Posted from TSR Mobile
 
 
 
Poll
Which pet is the best?

The Student Room, Get Revising and Marked by Teachers are trading names of The Student Room Group Ltd.

Register Number: 04666380 (England and Wales), VAT No. 806 8067 22 Registered Office: International House, Queens Road, Brighton, BN1 3XE

Quick reply
Reputation gems: You get these gems as you gain rep from other members for making good contributions and giving helpful advice.