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Advanced Higher Physics 2011-2012 Discussion/Help Thread

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Original post by Marcus4004
So what is an acceptable time? At our school you are allowed to take the paper as long as you don't leave the exam hall early...


Yeah exactly!

Also for 2bii) it tells you to calculate angular acceleration:

I found the angular velocity to be 1.33 rad/s and then used it and subed it into:

ω2=ω(o)2+2αθ\omega^2=\omega(o)^2+2\alpha* \theta

Then the angular displacement would be found by 2*pi*r (and since its a semi-circle wouldnt it just be pi?)

Getting it to equal 0.03 rad/s^2
(edited 11 years ago)
Reply 161
Original post by Aerofantastic94
Yeah exactly!

Also for 2bii) it tells you to calculate angular acceleration:

I found the angular velocity to be 1.33 rad/s and then used it and subed it into:

ω2=ω(o)2+2αθ\omega^2=\omega(o)^2+2\alpha* \theta

Then the angular displacement would be found by 2*pi*r (and since its a semi-circle wouldnt it just be pi?)

Getting it to equal 0.03 rad/s^2


I found the tangential acceleration by using
v2=u2+2asv^2 = u^2 + 2as
then using
α=a/r\alpha = a/r

IIRC still got the same answer.
Does anyone have the correct answer to 3bi, and ii? I always find I make a stupid mistake when calculating moment of inertia.
(edited 11 years ago)
Reply 163
Original post by CatherineCC
Does anyone have the correct answer to 3bi, and ii? I always find I make a stupid mistake when calculating moment of inertia.


For 3bi i got 18.63kgm^2
and for 3bii i just talked about the distribution of mass is not constant

Not sure if it's right, hopefully people will confirm mines :P
Original post by forsyth14
For 3bi i got 18.63kgm^2
and for 3bii i just talked about the distribution of mass is not constant

Not sure if it's right, hopefully people will confirm mines :P


Iirc that's what I got =)
Original post by forsyth14
For 3bi i got 18.63kgm^2
and for 3bii i just talked about the distribution of mass is not constant

Not sure if it's right, hopefully people will confirm mines :P


Oh dear, i put 37.2 kgm^2, not looking good for me :frown: What moment of inertia formula did you use?
Original post by CatherineCC
Oh dear, i put 37.2 kgm^2, not looking good for me :frown: What moment of inertia formula did you use?


I initially had that, it wasn't your formula, the problem was that you used 66kg instead of 33kg for both the "rods". Since they were equal masses and his overall mass was 66kg...

In any case: I=(1/3)mL^2, i think it was.
Reply 167
Original post by Aerofantastic94
I initially had that, it wasn't your formula, the problem was that you used 66kg instead of 33kg for both the "rods". Since they were equal masses and his overall mass was 66kg...

In any case: I=(1/3)mL^2, i think it was.


If what the above person is saying i wouldnt worry about it, at most it'll be 1 mark dropped... probably half a mark tbh. They're nice when you make small transcription errors in physics :smile:
Original post by Aerofantastic94
I initially had that, it wasn't your formula, the problem was that you used 66kg instead of 33kg for both the "rods". Since they were equal masses and his overall mass was 66kg...

In any case: I=(1/3)mL^2, i think it was.


Yeah thats exactly what i did :frown: Hopefully ill still get some marks...
Original post by CatherineCC
Yeah thats exactly what i did :frown: Hopefully ill still get some marks...


Yeah you will get atleast 1 and a half minimum for that... don't worry! :smile:
Original post by Aerofantastic94
Yeah you will get atleast 1 and a half minimum for that... don't worry! :smile:


Ok, thanks :smile: its just i was hoping for an A but i think i might just of missed it, so im trying to scape as many 1/2 marks as possible, haha.

What did you all get for the tension in the string, and the direction in 5biii?...
Reply 171
Original post by CatherineCC
Ok, thanks :smile: its just i was hoping for an A but i think i might just of missed it, so im trying to scape as many 1/2 marks as possible, haha.

What did you all get for the tension in the string, and the direction in 5biii?...


I got 0.043 N for the tension but my direction is wrong i think.
Original post by forsyth14
I got 0.043 N for the tension but my direction is wrong i think.

Oh good, well at least my tension is the same as yours :smile:... for direction i put '24degrees to the right from the original position of the sphere', but i have no clue if its right...
Original post by CatherineCC
Ok, thanks :smile: its just i was hoping for an A but i think i might just of missed it, so im trying to scape as many 1/2 marks as possible, haha.

What did you all get for the tension in the string, and the direction in 5biii?...


Have you seen the Google doc answer sheet?
Original post by Marcus4004
Have you seen the Google doc answer sheet?

yeah, but it never answered 5biii?.. Or am i just being stupid?
Original post by CatherineCC
yeah, but it never answered 5biii?.. Or am i just being stupid?


It was updated about an hour ago :smile:
If Marcus and the added changes are correct then I'm standing in around 74-80%... Not bad, but did the worst thing in Qu 8biii) where I did the working on my calculator, got it right, but didn't put it down in paper! :/
Original post by Aerofantastic94
If Marcus and the added changes are correct then I'm standing in around 74-80%... Not bad, but did the worst thing in Qu 8biii) where I did the working on my calculator, got it right, but didn't put it down in paper! :/


Ahhh man! Strathclyde here you come ;D
Could someone up the question paper so i will do a fully worked solutions
tomorrow morning!

Marcus4004 has put up answers: https://docs.google.com/document/d/1p-sGozwIqjeAIs2_dploKeBdvXqf9lFI3q64iuVBDhk/edit?pli=1
(edited 11 years ago)
Original post by tomctutor
Could someone up the question paper so i will do a fully worked solutions
tomorrow morning!

Marcus4004 has put up answers: https://docs.google.com/document/d/1p-sGozwIqjeAIs2_dploKeBdvXqf9lFI3q64iuVBDhk/edit?pli=1


Okay! Will do, 15 mins. Thanks.

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