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    (Original post by Hasib98)
    asked for magnitude bro so signs are irrelevant, a positive value should have been stated
    Ohhhhhh, I see. Thanks.
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    poll: http://www.thestudentroom.co.uk/show....php?t=4150305
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    (Original post by greg2321)
    For the moments question which is out of 7 marks I got the incorrect answer of M = 105 and d = but as far as i can see I did the same method as everyone who got the write answer so I must have just made a numerical mistake so does anyone have any idea of how many marks I could possibly get out of 7?
    4 seems reasonable
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    (Original post by E1Ephan7)
    I completely guessed 7a) F=2.5i and forgot to write j component. Showed no working. How many marks could i get? please someone?
    Maybe maximum half marks of the part I think. If no method then no Method marks. Out of curiosity how did you guess 2.5? If it was a whole number I could understand but it seems a bit random? Good guess and maybe if you had a diagram or something you could get a couple of marks perhaps but just the answer isn't worth much


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    (Original post by Don Pedro K.)
    Guys, for the magnitude of the force exerted on pan by brick, I got the right answer but I did it in a way which gave a negative answer for R. how many marks do you think I would lose?
    depends, can be all of them if the examiner is peak
    most likely to get some method marks
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    (Original post by Tb3636)
    For the impulse queation I found the value of u using suvat. But didn't read the queation properly and didn't attempt the impulse. How many marks do you think I will lose? Guessing three. Cheers
    Depends if you got u right, it was 3.5ms^1? It was out of 7 so yeah I would probably guess about max 3 marks
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    (Original post by TSRPAV)
    how are people getting 3Ns for impulse? i got 2.48 or something and it seems to work using kinematics,not sure how people are getting 3.5m/s for the velocity off the wall?
    I think I did that at first but then corrected myself, you used the force as the acceleration but actually you had to do f=ma first.
    Using the force as the acceleration would give you like 2.478.. or something like that
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    (Original post by Questioner1234)
    Yes it did ask for force on pulley due to string. I think what people mean is that the force is 45 to horizontal which is a bearing of 225.


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    (Original post by Hasib98)
    that was the question yes but i dont think the answer is given in bearing form, just an angle respective of the direction

    i just wrote diagonal cos i was confused LOOOL
    Thanks.
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    Worked answer to the moments question anyone where you had to find d?

    Don't know why but people at my school are saying d is 3. How did they get to that do you think and are they wrong?
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    (Original post by E1Ephan7)
    I completely guessed 7a) F=2.5i and forgot to write j component. Showed no working. How many marks could i get? please someone?
    wow what a badass guess LOOL so accurate but im not sure, perhaps none there was no evidence of working and you forgot to write the j component so sorry bro
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    (Original post by dodgewc25)
    Worked answer to the moments question anyone where you had to find d?

    Don't know why but people at my school are saying d is 3. How did they get to that do you think and are they wrong?
    Definitely wrong. The plank was non-uniform and of length 6m, so d cannot be 3 otherwise it is uniform.

    Generally people are getting 1.2 or 1.6.
    1.2 is the favourite.
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    (Original post by dodgewc25)
    Worked answer to the moments question anyone where you had to find d?

    Don't know why but people at my school are saying d is 3. How did they get to that do you think and are they wrong?
    Yeah they are wrong LOOOOL
    its 1.2 bby
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    (Original post by Questioner1234)
    Maybe maximum half marks of the part I think. If no method then no Method marks. Out of curiosity how did you guess 2.5? If it was a whole number I could understand but it seems a bit random? Good guess and maybe if you had a diagram or something you could get a couple of marks perhaps but just the answer isn't worth much


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    Same thing kind of happened to me... not really sure how I worked it out but I got an answer of 5/2 = p^2 where p was the value of i and j, so then I square rooted 5/2 which gave me root 10 /2.. so no idea what I did but I somehow got the answer 2.5 somewhere so do you think I will get any marks?
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    (Original post by matt1234512)
    what were the units for 42 i think wrote it as in newtons?
    You'll be fine.
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    (Original post by txnilxnur)
    Same thing kind of happened to me... not really sure how I worked it out but I got an answer of 5/2 = p^2 where p was the value of i and j, so then I square rooted 5/2 which gave me root 10 /2.. so no idea what I did but I somehow got the answer 2.5 somewhere so do you think I will get any marks?
    sometimes the mark scheme says if so and so number is seen, award this mark so hopefully you pick some up somehwere
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    (Original post by Questioner1234)
    Maybe maximum half marks of the part I think. If no method then no Method marks. Out of curiosity how did you guess 2.5? If it was a whole number I could understand but it seems a bit random? Good guess and maybe if you had a diagram or something you could get a couple of marks perhaps but just the answer isn't worth much


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    I just fiddled around with numbers on my calculator and got 2.5 for both but thought it wasn't right and only ended up writing it for the i component. I drew a diagram and wrote a couple of scribbly notes but no clear method.
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    (Original post by Don Pedro K.)
    that'd be alright hahaha
    Hope so
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    (Original post by Hasib98)
    sometimes the mark scheme says if so and so number is seen, award this mark so hopefully you pick some up somehwere
    Hopefully! Also.. how many marks do you think i will lose for drawing the graph without a point of intersection?
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    (Original post by LukeB98)
    This is how I did it. A bit of resolving for the deceleration after the rebound, then using kinematics equations to find the speed immediately after the collision. Then shove into impulse equation.

    R(-> F = 0.4a => R/8 = 0.4a, where R = 0.4g.

    So, a = g/8 ms^-2

    Then we must find the speed immediately after impact:
    s=5 , u=?, v=0, a=-g/8 (<- +)
    So you get: 0=u^2 - 12.25 => u=7/2 ms^-1

    I = m(v-u) => I = 0.4(3.5-(-4) = 3 Ns.
    Nah i did it like this:
    Mu= 1/8, initial velcoity=4m/s ,mass=0.4kg
    -----------------------------------------------------------------------
    Off the wall: R(<--): deceleration: a=- muR= 1/8*0.4*g=-0.49 m/s

    displacement s: 5m It comes to rest so v=0

    so we want to find U as that will be the final velocity off the wall,

    v^2=u^2+2as

    0^2=u^2+2(-0.49)(5) -------> U= sqrt(2*0.49*5)= 2.21 (2.d.p)

    So R(-->) m=0.4kg u=4m/s v=-2.21 m/s

    So I=m(v-u) = 0.4(-2.21-4)= 2.484 Ns and its impulse its a magnitude as both the wall and ball have the exact same impulse (i figured out for the other one/negative version)

    so i swear thats right??? still dont get how you guys got 3Ns
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    (Original post by student bang)
    7 marks
    That's physically impossible hahaha
 
 
 
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