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Physics review

  • 19-06-2006 12:06pm
    #1
    Closed Accounts Posts: 195 ✭✭


    Only just finished it a while ago. Left an hour early. This was due to me dropping down to pass just yesterday. I did everything bar one question. I have no regrets doing Pass, saw the honours and though it was impossible!!


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Comments

  • Closed Accounts Posts: 55 ✭✭Zeuz


    Did exactly the same :D, although I did not leave early I answered every single question, leaving early is not a good thing its only 3 hours out of your life ;)

    But yea i found it a bit diffferent not what I was expecting some of the stuff


  • Closed Accounts Posts: 8,880 ✭✭✭Raphael


    Did the honours, nice paper. Did Q1,2,4,5,6,7,8,9,10,12(a,b,c)

    Experiments gave me a fright, didn't know the formulae involved for 1 or 3. Then I realised you didn;t need the formula for 1. Happy days!


  • Closed Accounts Posts: 636 ✭✭✭NADA


    Raphael wrote:
    Did the honours, nice paper. Did Q1,2,4,5,6,7,8,9,10,12(a,b,c)

    Experiments gave me a fright, didn't know the formulae involved for 1 or 3. Then I realised you didn;t need the formula for 1. Happy days!

    Was a great paper. Experiments were easy 1,2,3 and then I did 5,6,7,9,10a,12(a and see). Looking at an a2 or maybe an a1


  • Closed Accounts Posts: 27 niamhy101


    really nice paper, did 1,2,3,4,5,6,7,8,9,10,12 a,b,c

    the experiments weren't all what i thought they would be, but ya cant predict them all!!


  • Registered Users, Registered Users 2 Posts: 348 ✭✭nedward


    In the expt. with the spectrometer, what was the angle you were given? Was it between the two diffracted second order images, or between the zeroth order and the second order?

    Good paper though.


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  • Closed Accounts Posts: 1,031 ✭✭✭whassupp2


    grand paper. Dis 1,2,4,5,7,9,11,12(a,b and d)

    Only hopin for C1/2


  • Registered Users Posts: 136 ✭✭HoboJesus


    nedward wrote:
    In the expt. with the spectrometer, what was the angle you were given? Was it between the two diffracted second order images, or between the zeroth order and the second order?

    Good paper though.

    "The second order image on the left and the second order image on the right." Twas the two diffracted second order images. :)


  • Registered Users, Registered Users 2 Posts: 348 ✭✭nedward


    Cheers. Thought that. Bloody stupid question.


  • Closed Accounts Posts: 648 ✭✭✭exiot


    Dropped down to pass because of my lack of studying, the big gap between exams really puts me off..

    Pass was easy, nothing much to it. I laughed at Question 11, nearly all the answers were in the paragraph given.

    Happy that I will never have to study physics again, one more exam left


  • Registered Users, Registered Users 2 Posts: 1,186 ✭✭✭Nichololas


    f=ma guaranteed in physics

    Guess not. :D
    Enlil wrote:
    Newton's Second Law and Speed of Sound in Air are tipped this year I think. I heard Verification of Joule's Law could also come up (last up in 2003).

    2 out of 3 ain't bad. :)

    Overall that went pretty good. Dropped maybe 10 marks in Section A (stupid "Find the resistance" :mad: ) The Electron only coming up in Q12 kind of limited my options for the rest of the paper. Did Qs 5, 8, 10a, 11, 12c and b. Only got 5/8 in 5 and didn't know some of the stretched string stuff in Q11. Otherwise nary a mark dropped. :) Give myself a B1 I'd say (I hope).


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  • Closed Accounts Posts: 160 ✭✭helles belles


    Q1.why was a small heavy bob used?
    Q.10 why were pairs of negative and positive pions produced?


  • Closed Accounts Posts: 1,031 ✭✭✭whassupp2


    :D
    Q1.why was a small heavy bob used?

    Because a big bob leads to air resistance and this slows down the movement of the bob. (thats what i sed. dunno is it right.)


  • Closed Accounts Posts: 172 ✭✭Zoodlebop


    whassupp2 wrote:
    :D

    Because a big bob leads to air resistance and this slows down the movement of the bob. (thats what i sed. dunno is it right.)

    Yea, I said that. I also said that it had to be heavy so that the string didn't go slack at the top of its swing.

    It had to be inextansible to the the bob didn't perform SHM, right?


  • Registered Users Posts: 41 DiscoMouse


    Ahahaha, I destroyed that paper! No surprises at all, avoided light completely, A1 easy. On to Chemistry!

    EDIT: And I said the string was inextensible so the length remaing constant during oscillation.


  • Closed Accounts Posts: 1,031 ✭✭✭whassupp2


    Zoodlebop wrote:
    It had to be inextansible to the the bob didn't perform SHM, right?

    Doesnt the bob perform SHM anyway??? I said that its because its a relationship between period and length the length must be kept constant or some rubbish like that.


  • Registered Users, Registered Users 2 Posts: 1,186 ✭✭✭Nichololas


    Well done DM. :p

    Small heavy bob:
    i) To keep string taut
    ii) Reduce air resistance, as opposed to a large heavy bob.

    Can't remember exactly why negative and positive pions are produced. Mass defect and conservation of charge springs to mind but I can't pinpoint exactly.


  • Closed Accounts Posts: 172 ✭✭Zoodlebop


    Did everyone derive the relationship between velocity and angular velocity by getting the length of the arc with radius r and angle Ø, then dividing that length by time. Angluar velocity=Ø/t and v=rØ/t

    => v=r(omega)

    Q.12 (a) Did ye get something similar?

    Pressure is scalar or vector?

    Pressure at bottom = 3 x pressure at top

    Lake depth = 20 point (something) metres


  • Closed Accounts Posts: 1,031 ✭✭✭whassupp2


    Zoodlebop wrote:
    Pressure at bottom = 3 x pressure at top

    Thats what i got. then i figured it must have somrthing to do with the 4 degrees so i changed it.


  • Closed Accounts Posts: 887 ✭✭✭Rockerette


    i thought it was a pretty ok paper, if i had been super studious, i woulda been grand. and in fairness i was grand. the usual, coulda do some bits, couldnt do other..


    the experiments were lovely, did 1, 2, 3

    Q5 was great, and Q12 was grand too


    and from there, i wished i coulda just picked and chosen buts and pieces from teh rest.. hehe..


    Did 6 (ahaha. ok, i did q6 based purely on the fact i knew the definitions.. for 12 marks.. did it at the end, i suck at circular motion, so i bet onyl 12 marks from that question...)
    7 (gosh. it wasnt difficult, but it confussed me)
    8 (knew about 1/2 of it.. guessed the rest :eek: )
    11 (why didnt i learn amgnetic flux related stuff? bastard me)



    So yeah, it was a grand paper, and for people who actually knew their stuff, i'd say they were flyin



    i wanted a B2. dont think i got it. i'll be HOPEFUL and go B3, but hhmm.. might be bordering on C material the more i think about it...


  • Closed Accounts Posts: 172 ✭✭Zoodlebop


    Enlil_Nick wrote:
    Can't remember exactly why negative and positive pions are produced. Mass defect and conservation of charge springs to mind but I can't pinpoint exactly.

    Aren't those particles produced to conserve the energy with which the protons collide, by carrying it away as mass?

    Damn, your right about the SHM. It is inextensible to keep the length constant. I may get some marks for "so it doesn't perform vertical SHM"

    "Three negativly charged leptons"

    Did ye know that?
    I said electron, negetron and zion:rolleyes:


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  • Closed Accounts Posts: 212 ✭✭sully-gormo


    That was a grand paper, was expecting it to be a bit easier but i still did ok.
    Does anyone know?:
    What are THE two negative leptons; I had a look through the book and I think that Q is wrong
    Why are + and - pions produced??

    Overall it was grand; hopefully I got the A1. I think anyone who was relying on a prediction did badly, that paper would have been impossible to predict


  • Registered Users Posts: 41 DiscoMouse


    Zoodlebop wrote:
    Aren't those particles produced to conserve the energy with which the protons collide, by carrying it away as mass?

    Damn, your right about the SHM. It is inextensible to keep the length constant. I may get some marks for "so it doesn't perform vertical SHM"

    "Three negativly charged leptons"

    Did ye know that?
    I said electron, negetron and zion:rolleyes:

    LOL

    It was only a passing mention in the chapter, but the other two negative leptons are the muon and the tau electron.


  • Closed Accounts Posts: 172 ✭✭Zoodlebop


    Overall I thought it was a luvly paper.

    For Q.2 did you divide the given angle by two to find the angle to put into

    n(lambda)=dsinØ

    ????


  • Closed Accounts Posts: 887 ✭✭✭Rockerette


    DiscoMouse wrote:
    LOL

    It was only a passing mention in the chapter, but the other two negative leptons are the muon and the tau electron.

    SCORE!

    i actually got soemthing right... ahahahahaa.. woo


  • Registered Users, Registered Users 2 Posts: 1,186 ✭✭✭Nichololas


    Zoodlebop wrote:
    Aren't those particles produced to conserve the energy with which the protons collide, by carrying it away as mass?

    Damn, your right about the SHM. It is inextensible to keep the length constant. I may get some marks for "so it doesn't perform vertical SHM"

    "Three negativly charged leptons"

    Did ye know that?
    I said electron, negetron and zion:rolleyes:

    Actually that's what I meant by mass defect, the difference in the energy/mass from the beginning and end of the equations. I said conservation of charge because that's why there's a negative AND a positive pion.

    And talking of silly answers, the experiment to verify Newton's 2nd Law must have been weighing heavily on my mind because I drew that diagram instead of the Joule's Law one. I was confused when I read over the paper, thinking; "Where the **** did that come from", then frantically scribbing it out and drawing in the right one. Infact that's less silly more full on retarded. The examiner's going to think I'm a retard. :cool:


  • Closed Accounts Posts: 8,880 ✭✭✭Raphael


    It's cool man, we ALL think you;re a retard. =p


  • Closed Accounts Posts: 41 sariane


    in the first experiment did u have to divide t by 25 first and then square it??? i completely forgot to divide by 25 cos i didnt think u had to!!


  • Closed Accounts Posts: 172 ✭✭Zoodlebop


    Enlil_Nick wrote:
    Actually that's what I meant by mass defect, the difference in the energy/mass from the beginning and end of the equations. I said conservation of charge because that's why there's a negative AND a positive pion.

    I'm not sure about that.....I thought that all the mass defect all went into the energy of the gamma rays, otherwise how would you know what mass went into the gammas and what went into pions. I think that the collision energy of the protons is converted into mass, mass in the form of pions. I'm not positive though. Sure 'tis only 6 marks :) What did you say for why 2 photons are produced? I said that the energy produced from the 2 protons is two great to be carried away by one photon.


  • Registered Users, Registered Users 2 Posts: 2,736 ✭✭✭OctavarIan


    Physics... made the mistake of not changing to ordinary on the day, totally got ****ed up the ass in the hons paper. :(


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  • Registered Users, Registered Users 2 Posts: 1,186 ✭✭✭Nichololas


    sariane wrote:
    in the first experiment did u have to divide t by 25 first and then square it??? i completely forgot to divide by 25 cos i didnt think u had to!!

    Uh I hope not because I don't do that either. I got a straight line graph though. :confused:


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