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    Hey only one I messed up was last one. For the last one I put the right magnitude but direction I put 045 degrees as bearing, how many marks do you think I'll lose
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    (Original post by KloppOClock)
    Message me if anything is wrong.
    Also, if anyone remembers how many marks each question was worth, please comment so I can add them on too.

    Question 1:
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    1(a) 104, (90+14)

    1(b) p = (400+15t)i + (20t)j
    q = (20t)i + (800-5t)j

    1(c) The 'j' vectors for both are equal, as it is due west.
    800-5t = 20t
    t = 32
    therefore q = 640i + 640j
    Question 2:
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    2(a) T = 20.6N
    2(b) 15.45 N => 15.5 N (3sf)
    Question 3:
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    3 Ns
    Question 4:
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    4(a)
    4(b) Area under graph = 975
    Area for slower car for first 25 seconds = 750
    975-750 = 225
    1/2 * b * 30 =225
    b = 15
    total time = 15+25 = 40
    so area under faster car = 975 = 1/2 * (40)(T+40)
    T = 8.75 s
    Question 5: (10 Marks)
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    μ=0.73 to 2 significant figures
    Question 6: (7 Marks?)
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    For 1st situation, R(T) = 0
    For 2nd situation, R(S) = 0

    M(S) => 0.5M = 30d-15
    M(T) => M = 60 - 15d
    Therefore,
    d = 1.2m
    M = 42kg
    Question 7:
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    7(a) F2 = 2.5i + 2.5j (this required simultaneous equations)
    (b) V = 12i +5j, thus speed = 13 ms-1
    Question 8:
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    8(a) Fmax = 0.3g
    acceleration = 0.6g
    Tension = 11.76N = 11.8 N (3sf)

    8(b) RF = √(11.76)^2 + (11.76)^2 = 16.6
    It has a bearing of 225
    For question 8b, what was the question asking? I thought they were asking for the reaction force of the tensions on the pulley, so I got the same magnitude as you, but for the direction I put down a bearing of 045.

    :/ Did I read the question wrong?
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    can someone explain how the got 15.45 something N for the pans reaction? i got 5.15N because it said reaction of the brick of the pan..?!
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    (Original post by Racheli)
    can someone explain how the got 15.45 something N for the pans reaction? i got 5.15N because it said reaction of the brick of the pan..?!
    R - 1.5g = 1.5a
    Since a was 0.5ms-2,

    R - (1.5x9.8) = (1.5x0.5)
    R - 14.7 = 0.75
    So R = 14.7 + 0.75 = 15.45
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    (Original post by Assmaster2)
    Hey only one I messed up was last one. For the last one I put the right magnitude but direction I put 045 degrees as bearing, how many marks do you think I'll lose
    Probably just 2 marks lost then
    • Thread Starter
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    (Original post by JamieeLL)
    So on the last question i completely missed out the fact it said 'and direction' so i didn't say southwest or 225degs or anything but I did just out of chance draw the arrow in the right direction on the diagram that they provided. Does this get you any marks or no?
    in one of the exam solutions videos, it said it was okay if you annotated the angles
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    Does anyone know the marks for each question
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    Alright so I got everything correct except for thr impulse question I did a minus error and got 0.2 instead of 3, and on the very last question I got the right answer but didnt specify a direction. How many raw marks or UMS do you think I got?
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    I understand that but I'm confused why you're using 1.5g and not the weight of the pan 0.5g as it asked the reaction of the brick on the pan
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    (Original post by Racheli)
    I understand that but I'm confused why you're using 1.5g and not the weight of the pan 0.5g as it asked the reaction of the brick on the pan
    You use the weight of the brick, not the pan in this situation.

    I'm not too sure how to explain this properly.

    https://youtu.be/0dDtHonctTg?t=6m55s

    This vid pretty much explains it. The bottom situation in the 2nd column is the one applicable to our question.
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    I've added the marks, I'll start adding some model answers.
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    (Original post by Haamoo7)
    You use the weight of the brick, not the pan in this situation.

    I'm not too sure how to explain this properly.

    https://youtu.be/0dDtHonctTg?t=6m55s

    This vid pretty much explains it. The bottom situation in the 2nd column is the one applicable to our question.

    okay haha i'm not explaining myself well. the general rule is that when it asks you to find the reaction of A on B, you only focus on the mass of B. so when it asked us to find the reaction of the brick on the pan, surely you would use the weight of the pan and not the brick?
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    (Original post by Racheli)
    okay haha i'm not explaining myself well. the general rule is that when it asks you to find the reaction of A on B, you only focus on the mass of B. so when it asked us to find the reaction of the brick on the pan, surely you would use the weight of the pan and not the brick?
    "find the reaction of the brick on the pan"
    If you replace the word pan with "ground", and imagine the brick was lying on the ground, how would you find the reaction of the brick on the ground? You would use the weight of the brick, not the weight of the ground.

    Same concept applies here. Treat the surface of the pan like it's the ground. Therefore the weight of the pan is not applicable, and you would use the weight of the brick instead.
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    Posted from TSR Mobile

    Please add the solution to the moments question. Thanks
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    does anyone remember the marks for each question?
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    Hey guys also for 1(b) p = (400+15t)i + (20t)j
    q = (20t)i + (800-5t)j

    I wrote p = 400i + t(20j+15i)
    and for q = 800j + t(20i-5t)

    I saw in mark schemes this is sometimes how they write it, it means exact same thing, do you think I will get full marks for this?
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    Are you sure that for question 5, μ was to 2 significant figures and that 8b asked for the angle?
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    For people who got d=1.6 and m=66 because of using wrong distance....if we showed all working how many marks would we get out of the 7?

    Also i drew the graph correct except the 30ms graph decelrated before the 40ms line so the area was less/wrong....how many out of 4 if everything else was correct?

    Also for some reason i think i got exactly double th etension in q8....i used the correct method for part b...do i get ecf?

    Thanks for anyone who can help
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    can someone show q7 a working out?
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    anyone remember the details of question 3?
 
 
 
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