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# Official OCR A G481 mechanics 20th May 2013 watch

1. Mty mark scheme posted.

Electronic copies of the paper wont be available for quite some time
2. (Original post by MikeyP96)
i put it was the same as the component of the weight down the slope/parallel to the slope since the raindrop is stationary
I put this also, is there an uniffial marks sheme so i can work out what i think i might have gotten?
3. (Original post by cyiarik)
i remember some answers but not the actual questions they were answering :P , so ill just post random answers i got

kgm^-2
giga is 1000 times bigger than mega
density = 1.6x10^-? kgm-3 [forgot what it was to the power of]
force constant is the force per unit extension
R=1.4x10^-5 and F=6.3x10^-5 (something close to the) the F is the same because the raindrop is stationary/in equilibrium

3.5ms^-2 for instantaneous acceleration of a trolley i think
I got ratio of B/A as 2.8N
the moments question i got x(50-x)=12x and i think the answer was 0.37m

-power is rate at which work is done
-work done = 5.4x10^?
-output was 390 Watts
-Input was 1228 Watts / 1.3x10^3 Watts

i wrote for one question something about weight being smaller than drag at t=0.05 because the ball was decelerating and then at t=0.25 they were equal/there was zero acceleration

for the Youngs modulus question i got 1.9x10^9 Pa
Apparently the graph of stress/strain would remain the same :L

For the last question i wrote that it was polymeric but forgot to finish my explanation of why it was good for aeroplane tyres (doh!) :L

i basically fluffed my way through the explanations; dont think i did that well tbh :L did anyone get similar answers to me?

I got alot of the same answers as you but a few differences here and there
4. (Original post by yodawg321)
What did people say about the forces of graph.

For the first point I said about the drag force being greater than the weight force which means it deaccelerates.

And for the second point I put about the weight and drag forces being equal which makes constant velocity.

anyone say anything like this?
Yeah that was right i think, what did you pur for the ball accelerating with springs b and a ??
5. (Original post by teachercol)
Mty mark scheme posted.

Electronic copies of the paper wont be available for quite some time
did you say the mark scheme has been posted ?
6. (Original post by harrydry)
did you say the mark scheme has been posted ?
were lol
7. (Original post by sohailkm96)
For the perpendicular component you need to use the cos of the angle, so it was 8x10^-5 (if im right) x cos30

For the parallel component you need to use the sin of the angle, so it was 8 x 10 ^-5 x sin30
Are you sure it was ^ 10 -5 I thought it was ^ 10 5
8. (Original post by Legal drugdealer)
were lol
i see no mark scheme anywhere?!?! am i just being stupid
9. you guys just like torturing yourselves for no reason, just wait till you get your marks stop estimating what you got that would be pointless!
10. (Original post by nickiminajs)
Are you sure it was ^ 10 -5 I thought it was ^ 10 5
its a raindrop, dont think it was going to be that heavy
11. Did anyone else complain about the spring question? The way it said spring a was extended aswell as spring b, instead of compressed for spring A? probably lost a few people marks! did it wrong at first til i used common sense and got 3.5! not too awful of a paper, easy to make silly mistakes, annoyingly i did 100000 cm3 in 1m3 but its 1000000 instead! ah!
12. (Original post by nickiminajs)
Are you sure it was ^ 10 -5 I thought it was ^ 10 5
i dont think a rain drop would have a force ( weight ) of 1000000N
13. (Original post by laurence231)
Did anyone else complain about the spring question? The way it said spring a was extended aswell as spring b, instead of compressed for spring A? probably lost a few people marks! did it wrong at first til i used common sense and got 3.5! not too awful of a paper, easy to make silly mistakes, annoyingly i did 100000 cm3 in 1m3 but its 1000000 instead! ah!
Both springs can be extended..it's just one was extended more than the other.
14. (Original post by mathphysics)
i dont think a rain drop would have a force ( weight ) of 1000000N
Hahahha oh yeah lol xD
15. (Original post by Joe899)
Both springs can be extended..it's just one was extended more than the other.
but spring a was compressed from 0.5 to 0.3 meters wasnt it? the wording of the question implied it was stretched i reckon! i might be wrong as im crap at reading questions fully anyway, aslong as others got 3.5ms^-2 then im happy!
16. (Original post by laurence231)
but spring a was compressed from 0.5 to 0.3 meters wasnt it? the wording of the question implied it was stretched i reckon! i might be wrong as im crap at reading questions fully anyway, aslong as others got 3.5ms^-2 then im happy!
Oh..I can't remember either to be honest, but I also got 3.5 for the acceleration
17. Was you allowed to do the arrow for the force on trolley in pencil?!
18. according to the unofficial mark scheme i have lost around 10 marks
19. (Original post by teachercol)
Mty mark scheme posted.

Electronic copies of the paper wont be available for quite some time
Where have you posted your mark scheme? :/
20. (Original post by Joseph-)
you guys just like torturing yourselves for no reason, just wait till you get your marks stop estimating what you got that would be pointless!
Not really i can have rough estimate of how badly i've done so i dont end up crying in front of everyone on results day.

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