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OCR Physics A Breadth of Physics (24th May 2016) Discussion

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Original post by samendrag
i got 10^-something i cant remember but i got the number density to be 1.33x10^something


Same :smile:
what did ppl get for the AB wave question asking bout motion
Original post by guitar167
I thought it was total energy, because of the conservation of energy means
energy in =energy out just in different forms. Can anyone confirm??


yup total energy and momentum
Reply 403
Original post by Parhomus
Yeah I got the 5% uncertainty so when I got the answer I did 60x5/100=0.3


Yeah I dont know why I multiplied it by two...made a lot of mistakes on that paper
Reply 404
Original post by Parhomus
Don't u just divide the power by the energy per photon since power is energy per second.


Yeah thats what I did, I worked out the photon energy and didvided the power by the photon energy
Reply 405
Original post by isaac_wood_
Yeah the gradient was 16 but that was equal to 2a as u^2/x = 2a, so a = 8 (I think)


Yep you're correct and then just use f=ma using the mass of 920kg:smile:
Reply 406
For the first question where you were asked to work out the time, did you get 0.73 or something?
Original post by voltz
For the first question where you were asked to work out the time, did you get 0.73 or something?


Yep
Did anyone else get C for an abornmal amount of multiple choices?
what was it out of boys, and what d'yas reckon for the boundarys?
Original post by AshishSingh04
Did anyone else get C for an abornmal amount of multiple choices?

Yeah I was thinking the same, glad I'm not the only one
Original post by JAFF2400
What were the two conserved physical quantities in the inelastic collision (comet or whatever)? I think it was 1 mark, i knew momentum was one, I didn't put kintetic energy because its not conserved in inelastic collisions, so randomly put mass lol. I heard someone say it was momentum and total energy is that right?


Yeah that's correct. Kinetic energy is only conserved in elastic collisions. I don't know why but I ca never seem to remember that difference.
Original post by voltz
For the first question where you were asked to work out the time, did you get 0.73 or something?


Yeah I got something like that.
Original post by AccountingHelp
Yeah I was thinking the same, glad I'm not the only one

what was the very last question?
Original post by julesaquilina
i think i put 6.5


I thought that was right.
Original post by sddsfsdafs
Did anyone get 16 for elastic potential ratio?


Yeah I did. It so often seems that the amount of silly theoretical crap for some mcq's is just disproportionate to the amount of marks.
Ive done the paper and I'll post up my answers and mark scheme later today.
Its quite a tough one - still that means low grade boundaries.
Original post by viktorh
got 6.8 m/s for the speed of the carbon atom after the collision with the hydrogen atom. Seemed a little small to me but the carbon atom is massive in comparison so Im hoping that's right


Yeah i got that too. The collision is perfectly elastic so there's no reason to suggest that momentum is not conserved, and the carbon is 11 times bigger than the hydrogen. I think we got this right.
Original post by Barklimus
Yeah i got that too. The collision is perfectly elastic so there's no reason to suggest that momentum is not conserved, and the carbon is 11 times bigger than the hydrogen. I think we got this right.


i dont think so because the 420 m/s would have been negative so you should have got an answer in the 70s
Original post by teachercol
Ive done the paper and I'll post up my answers and mark scheme later today.
Its quite a tough one - still that means low grade boundaries.


cheers man how low do you think grade boundaries will be

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