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AQA Physics A Unit 2 5th June 2009 [New Spec]

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Chriz M

I think TSR is correct, but I'll read into it. But getting a 270/300 UMS or above, will help persuade your school to predict you an A*.

Dogie, could you tell use which page it is one the specification?

I am pretty sure it was 80 average in AS, 90 average in A2 and total over 480.

And even if you get an 80 average, you can persuade your school to predict you an A* grade if they think you deserve it and will work hard for it.

... :smile:

Reply 341

kayn

***Hannah***

i was told by these oxford/cambridge teachers who i met that being predicted A* wont be an advantage, they actually said they didnt want predicted A* because they will make you high offers and that.

Reply 342

dogie

Chriz M

I think TSR is correct, but I'll read into it. But getting a 270/300 UMS or above, will help persuade your school to predict you an A*.

Dogie, I'm not sure where you read your statement, but on page 55 on the spec, section 5.7. This is a quote from it.

"To be awarded an A*, candidates will need to achieve a grade A on the full A Level qualification and an A* on the aggregate of the A2 units."

In fact this suggest you might be able to get a B in AS, and 270/300 UMS in A2 modules, you will still get an A*, as that would be an A normally and an A* on A2 aggregate.

I know it says that but thats a requirement, and actually physically you need an A in AS to get an A* in A2 (because even 79+100/2 cant get 90 average).

Wtf ive actually looked for it and i cant find it anywhere :/ Maybe TSR is right, and I thought in maths the a* was c3+c4+ other

Reply 343

fabregassed

sr1

Q1. (a). cyclist and cycle coming down of 68kg i think and they reach horizontal at 16ms-1
calculate the K.E
(b). Calculate the G.P.E when and the height was 12m
(c). The workdone by the 'CYCLIST' was 2400J, Account for the difference between K.E and G.P.E of the 'cycle and the cyclist'
(d) calculate the time taken
(e)calculate the average force or something

Q2. 22,000 kg container being lifted by four cables, piller p 32m away frm the end which is lifting the container and counterweight on the otherend
(a) calculate the tension in each cable
(b) calculate the moment of force
(c) what would prevent the crane from toppling over and explain why?
(d) calculate the tensile stress in each cable when the cross sectional Area of each cable is 3.8 *10-7
(e) show that the cables were extended by 17mm

Q3.a steel ball is dropped into a container containing a liquid, the distance between the liquid's surface and point of release of the ball is 0.16m
(a). calculate the time taken for the ball to reach the surface of the liquid
(b). calculate the speed just before it enters the liquid
(c) Explain how the speed and accerelation of the ball is varied when it enters the liquid(6 marks)

Q4.The student investigates how the extension of a rubber cord is varied with increasing and decreasing force
(a). Explain why the cord does not obey hooke's law
(b). What feature of the graph represents the plastic behaviour(something like tht)
(c). Dont remember
(d) explain with an aid of a diagram how would you carry out the same investigation(6 marks)

Q5. Progressive wave travelling from left to right. (Diagram shows the length 0.5m)
(a) calculate the wavelenght.
(b) calculate the speed when frequency = 22Hz
(c) calculate the phase difference between X and Y particles

Q6. Figure 3 shows a fibre core covered with cladding, the core has a refractive index of 1.55 and the cladding has a refractive index of 1.45
(a) [IN THE DIAGRAM THE ANGLE OF INCIDENCE WAS 60.0 degrees)
Calculate the critical angle
(b) explain why the light is not totally internally reflected
(c) Explain how cladding is useful on the fibre optic

Q7. a light of 590nm is pointed at a diffraction grating
(a) the distance between the grating is 1.67 * 10-7( i think)
calulate the angle of the second diffraction order
(b) show that orders higher than 2 cannot exist
(c) Light is replaced by another monochromatic light, calculate the wavelenght( dont remember the measurments tht they gave in this question)

nice memory?? :biggrin:

Reply 344

Chriz M

dogie

I'm not sure if you are confused, you need a total greater than 480 UMS, or above with at least 270 UMS coming from A2 Modules.

In maths you need 90+ in C3 and C4, and an A overall. For further maths, your top 3 A2 modules must be 270 UMS above with an A overall for an A*, therefore for F.M. if you took, 2 AS, and 4 A2 modules, then only your best 3 would count towards the A*. I'm taking 15 maths modules so I need 90s in C3, C4 for maths, and 90s in 3 A2 modules to get an A* in further maths.

Reply 345

sr1

G550NDH

Great... have you got the answers by any chance? :o:

And the question u dont remember i think was what does the area under the graph signify...

yh i think it was tht, it asked what does area under the graph represent

Q1.a) k.e = 8*10^3 J
b)g.p.e = 8.7*10^3J
c) k.e - g.p.e = 700J lost as heat due to friction and other resistive forces such as air resistance
d)time = 20s
e) avg.force = 54.4N

Q2
a) 22,000*9.8 / 4 to get tension in each cable = 53900
b) 22,000*9.8*32m = moment of force
c) clocking wise or anticlockwise moment frm counterweight will make the turning effect = 0 so the crane will not topple over
d) 22,000*9.8 / 4 = Force .. tensile stress = force/area
so 53900/3.8*10^-7
e)young modulus for steel = 2 *10^11
so rearrange the young modulus equation to get e=FL/AE where E = young modulus and then u get 17mm

Q3.
a)0.18s
b)1.77 ms-1
c)too long, juss say liquid applies a resistive force against the motion of the ball and as it moves its velocity becomes constant(terminal velocity) after deceleration due to resistive force so resultant force = 0 or balanced out and relate to newton's first law. i wrote more but dnt remember

Q4
a) coz the graph does not show a straight line(changing gradient) thereforce no proportionality between the force needed and the extension of the cord frm its natural lenght.
b)whtever tht was i juss wrote the graph comes back to origin so no plastic deformation, the cord can b easily stretch and return to its original lenght.
c)area under the graph= work done as it was force agaisnt extension graph
d)juss tell them how to carry out the same exp

Q5
a) i dont remember my answer
b) c=f*wavelenght
c)dnt remember my answer

Q6
a)sin-1(1.45/1.55) = 69.3 degrees
b)angle of incidence does not exceed the critical angle so light is not internally reflected
c)data security, cladding prevents light frm escaping and entering other cores or fibre optics so tht confidential data like bank accnt details dnt arrive at the wrong destination and be stolen. fibre optic becomes wet or scratched data is still protected by the cladding

Q7
a) 45 degrees
b) theta = 90 degrees so using the formula dsine(theta)=n*lamba
put in 90 degrees and make n the subject to get n=d/lambda and get 2.83 which is max order therefore no order higher than two exists.
c)5.67 * 10^-7 or sumthing.

Reply 346

sr1

fabregassed

nice memory?? :biggrin:

i dnt kno. i dnt remember everything but thanks anyway

Reply 347

East Stah

furry747

Well, at first I thought it was a calculation...

Then I think you had to explain the difference in E_p and E_k and say that E_p decreases due to travelling down, and E_k increases as velocity increases. But as you reach terminal velocity, E_p reduces, but E_k stays constant, and this is where the work done to overcome friction comes in. Thats what I wrote anyway, and it gave you lines, not a blank space which meant to me they wanted an explanation.

They did say in the question "Account for...".

For the first part (the bike bit) did you get something like 8700 for potential and 8000 for kinetic energy?

for that question i think they were looking for reasons why not all the work done was transferred to Ke.
As well as a just stating the work done made up for the Ep and Eg difference.

i said friction air resistance lol :tongue:

Reply 348

East Stah

Haruhi

OMG THAT EXAM PAPER WAS WEIRD.

Seriously... some of the questions I didnt know what to calculate!

Did anyone do the rubber extension question that was 6 marks?
I put the stand clamp and attatched the rubber, measure it, add known mass, measure length of rubber again, calculate delta L and find K using the equation F=KdeltaL.
Do repeats to increase accuracy and plot a graph of force against extention.

...please someone telll me Iam right... T__T I swear I am gonna cry if thats wrong.

I did basically that but i also spoke about removing weights on the way back to 0 force acting on the rubber band to show the unloading curve as well :s

Reply 349

East Stah

Chriz M

Basically for the sciences Ive learnt that you NEED any A in all your AS exams and then 90 + UMS For all your A2 exams. You need the 90+ Ums in each A2 exam otherwise you cant get it no matter how high your AS UMS's were

Reply 350

Chriz M

East Stah

I think the largest uncertainty is whether it is 90% mean or average. The syllabus states aggregate, so that implies just a mean 90% UMS.

Reply 351

kayn

http://www.qca.org.uk/qca_4076.aspx that link makes it pretty clear.

Reply 352

East Stah

kayn

http://www.qca.org.uk/qca_4076.aspx that link makes it pretty clear.

yep exactly what ive beeen told but im not sure about how the maths is gonna work :s

Reply 353

kayn

East Stah

yep exactly what ive beeen told but im not sure about how the maths is gonna work :s

good point because of the fact there modules , but my bet is there the same because i feel the whole A* reflecting mainly A2 is because the A2 are harder. if you get me. but , i can see why people question it in maths but i feel it will be the same as c3 and c4 are harder then c2 c1 for example but i dont know how they will compare like m1 to d1 or to s1 , because for example at my school we do s1 c1 c2 then d1 c3 c4 , clearly c3 c4 are harder but , d1 is comparable to s1 i guess :s