OCR Physics A G481 Mechanics [Thursday 17th May 2012]

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  1. striver17's Avatar
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    Re: OCR Physics A G481 Mechanics [Thursday 17th May 2012]
    (Original post by JohnSimmons)
    Did you work use SUVAT to work out displacement? Then put that into work done is force x distance? Then divide by time?

    That's what I did but I cant remember my answer :\

    Also, what was the answer to the previous question. The one where you had to work out the force of the spring or something?
    i did that...but i thought you divide the time by 2 coz ur working out half the distance??? i dunno....i was not very confident with it....
  2. James_Rogers's Avatar
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    When both rockets A an B are on, the forces are equal so there is a torque which produces a turning force/rotational force- so it rotates?
    When just A is turned on, the net force favours the direction of A since A>B. I think?


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  3. blackhole's Avatar
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    Re: OCR Physics A G481 Mechanics [Thursday 17th May 2012]
    (Original post by stackemup)
    Yes so happy, took me quite a bit of working, but I got 2.6 as well.

    Damn, that 5 mark deforming solids qualitative question took the absolute p***.
    could you remind me what question was this? cant even remember!
  4. Rough Silk's Avatar
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    Re: OCR Physics A G481 Mechanics [Thursday 17th May 2012]
    (Original post by blackhole)
    could you remind me what question was this? cant even remember!
    It was a glider and a spring. You had previously worked out the force. You are then given a time of 0.094 seconds (I think) and are told to work out the rate of work done.
  5. Ihatemathsexams's Avatar
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    Re: OCR Physics A G481 Mechanics [Thursday 17th May 2012]
    (Original post by blackhole)
    could you remind me what question was this? cant even remember!
    Well there was a spring with force constant 50 and was compressed by 0.07 metres. The time the force was applied for - or something like that - was 0.094 seconds.
    Really interested as to how everyone got 2.6 as i could not do this question for the life of me!
  6. TwinAz's Avatar
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    Re: OCR Physics A G481 Mechanics [Thursday 17th May 2012]
    I messed up this exam.
  7. James_Rogers's Avatar
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    Re: OCR Physics A G481 Mechanics [Thursday 17th May 2012]
    Wasn't the energy stored in the spring 1/2kx^2
    So the energy stored was 0.5 x 50 x 0.07^2 = 0.1225 j
    So energy done per second is 0.1225 / 0.094 = 1.30

    I left my answer as 1.30 so I must of missed something... but oh well.
  8. striver17's Avatar
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    Re: OCR Physics A G481 Mechanics [Thursday 17th May 2012]
    sooo not looking forward EWP...
  9. JuxtaposedJames's Avatar
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    Re: OCR Physics A G481 Mechanics [Thursday 17th May 2012]
    I got 2.6 but just realised its 1.3

    I did work done/time

    So I did the force x distance / time

    However work done for a spring is area under a graph

    So its half the force times distance / time which is 1.3

    Bugger
  10. striver17's Avatar
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    Re: OCR Physics A G481 Mechanics [Thursday 17th May 2012]
    (Original post by JuxtaposedJames)
    I got 2.6 but just realised its 1.3

    I did work done/time

    So I did the force x distance / time

    However work done for a spring is area under a graph

    So its half the force times distance / time which is 1.3

    Bugger
    crap! i did the same thing...
  11. JuxtaposedJames's Avatar
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    Re: OCR Physics A G481 Mechanics [Thursday 17th May 2012]
    (Original post by striver17)
    crap! i did the same thing...
    I think everyone did as everyone thinks 2.6 is the right answer...
  12. emah123's Avatar
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    Re: OCR Physics A G481 Mechanics [Thursday 17th May 2012]
    can someone please make an unofficial markscheme???
  13. sarah-xx's Avatar
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    Re: OCR Physics A G481 Mechanics [Thursday 17th May 2012]
    (Original post by Butterkist123)
    I thought the angle was 31 not 59. Because it went 30 up and 18 across..not the other way round.
    Yeah, I agree with you. I got 31 too...
  14. James_Rogers's Avatar
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    Re: OCR Physics A G481 Mechanics [Thursday 17th May 2012]
    (Original post by sarah-xx)
    Yeah, I agree with you. I got 31 too...
    Me too
  15. Butterkist123's Avatar
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    Re: OCR Physics A G481 Mechanics [Thursday 17th May 2012]
    31 is wrong.. :'( apparently it said between horizontal
  16. mora11's Avatar
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    Re: OCR Physics A G481 Mechanics [Thursday 17th May 2012]
    (Original post by emah123)
    can someone please make an unofficial markscheme???
    If somebody has the paper I will make an unofficial mark scheme, I can remember most of the questions and answers but I really don't want to do a MS without the paper tbh, I got around 53-54/60 Which should hopefully be 90+ UMS I would suspect based upon previous boundaries.
  17. Butterkist123's Avatar
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    Re: OCR Physics A G481 Mechanics [Thursday 17th May 2012]
    Who gets access to the paper after we've done it? Is it only teachers?
  18. .Username.'s Avatar
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    Re: OCR Physics A G481 Mechanics [Thursday 17th May 2012]
    What do people reckon full ums boundary and A boundary will be

    from answers i remember: radius = 10
    Force for glider question was 3.5N
    work done or whatever it was for that question i got 1.30 cause work done is 1/2fx not fx
    mass 119kg
    for the further reason why it is better for last question i said about energy supply is constant
    2 angle questions i got 11 something and 53 i think
    efficiency 27.3% rounded

    WHAT WAS THE ROCKETS ABOUT NET FORCE OR NET MOMENT? cause how can you assume that it creates a turning effect
  19. .Username.'s Avatar
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    Re: OCR Physics A G481 Mechanics [Thursday 17th May 2012]
    and what did people for the initial KE question, i said that energy was not totally transferred from KE to GPE
  20. JuxtaposedJames's Avatar
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    Re: OCR Physics A G481 Mechanics [Thursday 17th May 2012]
    (Original post by .Username.)
    and what did people for the initial KE question, i said that energy was not totally transferred from KE to GPE
    Only the vertical component of kinetic energy will be converted.
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