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# Official OCR A G481 mechanics 20th May 2013 Watch

1. (Original post by Boy_wonder_95)
So if you got an A why did you resit?
Why not?
are you taking A2 ?
Nope I'm still in AS
3. (Original post by Dominic101)
Why not?
But you already got an A... so what's the point?
4. (Original post by Boy_wonder_95)
Nope I'm still in AS
no I meant are you continuing to do A2 physics next year ?
5. This exam was really tough... it seemed more like an exam of understanding all of the possible exam tricks than physics, like how on the stress/strain graph the strain was given in %...
6. (Original post by Clem Rossa)
This exam was really tough... it seemed more like an exam of understanding all of the possible exam tricks than physics, like how on the stress/strain graph the strain was given in %...
Why is everyone saying that you had to convert the percentage????? You did not have to convert it as strain doesn't have any units you can convert it to, right?
7. (Original post by CA\$H KRAZE)
Why is everyone saying that you had to convert the percentage????? You did not have to convert it as strain doesn't have any units you can convert it to, right?
yes strain has no units but the percentage strain is= (x/L)x 100 so to get the original strain you divide the % by 100... I hope so because that's what I did. because if you think about - the wire would have extended by 80cm if you simply used 0.8m but an extension of 0.008m is more plausible- I hate how I got all the easy marks wrong and I understand these little evil schemes from the examiners
yes strain has no units but the percentage strain is= (x/L)x 100 so to get the original strain you divide the original by 100... I hope so because that's what I did. because if you think about - the wire would have extended by 80cm if you simply used 0.8m but an extension of 0.008m is more plausible- I hate how I got all the easy marks wrong and I understand these little evil schemes from the examiners
Okay, that makes sense, guessing I will only pick 1 mark out of the possible 3 marks then I think this paper would have been more accessible to those doing maths A-Level as the amount of maths you had to do was overwhelming!
9. (Original post by CA\$H KRAZE)
Okay, that makes sense, guessing I will only pick 1 mark out of the possible 3 marks then I think this paper would have been more accessible to those doing maths A-Level as the amount of maths you had to do was overwhelming!
hmm now that you mention it, there was the moments question as well, where you ended up having to do some algebra.
I just hated all the force questions I think I lost anywhere from 30-35 marks, hopefully i'll get a D or above so I can get C overall and drop physics
10. (Original post by Dominic101)
Why not?
I'm thinking, the higher you get in g481, the lower you can get in g482 and still get an A?
11. (Original post by Boy_wonder_95)
It was 41 in Jan and that was easier.
That's a bit low. I must be used to further maths, where its about 61/75 for an A

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if we are on about the same question, that's what I thought until I heard everyone talking about the force F being the same as something because the raindrop was in equilibrium- seriously fml i'm so sc****d, I just put it's 0 because cos90=0
I put zero too I hope that's right

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13. (Original post by Hannahm1995)
I put zero too I hope that's right

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I put 0 too, I just remember being taught that if it is perpendicular to the slope then it is zero because it is cos90
14. (Original post by Dan_JR_12)
I put 0 too, I just remember being taught that if it is perpendicular to the slope then it is zero because it is cos90
That's what I exactly put. I dont think its fair how we were given two different angles and it was very confusing for how long the exam is

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15. (Original post by Dan_JR_12)
I put 0 too, I just remember being taught that if it is perpendicular to the slope then it is zero because it is cos90
You're right in that cos90 does equal zero, however there was a component of the weight acting both parallel and perpendicular to the plane. The component of the weight parallel to the slope was the only force in the same plane as F, and since you know it is in equilibrium, the two forces must be equal.

As for just resolving the components, you are told the plane is at angle of 30 degrees to the horizontal, which means that the component of the weight perpendicular to the slope will be 30 degrees to the right of where it was drawn. You then use cosine to 'close' the angle.

Btw sorry if the diagram is unclear...

(Didn't mean to send this twice btw)

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16. (Original post by Rhodopsin94)
You're right in that cos90 does equal zero, however there was a component of the weight acting both parallel and perpendicular to the plane. The component of the weight parallel to the slope was the only force in the same plane as F, and since you know it is in equilibrium, the two forces must be equal.

As for just resolving the components, you are told the plane is at angle of 30 degrees to the horizontal, which means that the component of the weight perpendicular to the slope will be 30 degrees to the right of where it was drawn. You then use cosine to 'close' the angle.

Btw sorry if the diagram is unclear...

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17. Really hope the grade boundaries are low, I found it hard! I don't do maths either

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18. how did everyone find it???
19. (Original post by JackLambourne)
That's a bit low. I must be used to further maths, where its about 61/75 for an A

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that's around the usual 80% mark and the January were only really low because the exam was difficult but personally I think this was a lot harder
that's around the usual 80% mark and the January were only really low because the exam was difficult but personally I think this was a lot harder
I think this was so so so much harder! I just hope others did too so the boundaries are lower/the same :/

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