AQA AS Physics A Unit 2 25/05/12 - PHYA2

1a)i. Two Vectors
Force, velocity, acceleration, displacement etc.
ii. Two Scalars
Mass, distance, speed, energy etc.
b)Two forces on the helicopter
Air resistance
Weight
c)Triangle of forces means no resultant force, so in
equilibrium, so has no acceleration.
d)Weight=Fsinx
Can't remember the force or angle.

2a)GPE to KE from A to B, then KE back to GPE from
B to C. No energy lost due to friction/air
resistance, so mgh=0.5mv^2
b)Curve with decreasing gradient, then becomes
straight from B onwards.
c)Object remains at constant speed, because it is
acted on by no forces, and hence no resultant
force so no acceleration.

3a) Moment=Fd, in Nm
b)
c)

4a) Cladding
b)
c) I did 180-90-angle of incidence to get the angle
of reflection
d) Use n1sini=n2sinr
e) Multipath dispersion, pulse merging, loss of
information.

7a) B was longitudinal as the direction of vibration
was parallel to the direction of motion
b) Wavelength maybe from one area of
rarefaction to the next
c) Arrow up for transverse
I did an arrow left for the longitudinal but
not sure
d) EM waves are plane polarised. Aerial must be
aligned into correct plane to recieve them

Can people please clarify things and chip in

Not saying these are right just saying what I put. Copy/paste and add to this...

Reply 981

MSI_10

15

Original post by lemongrass

No.

There is nothing about terminal velocity in this question.... The speed was constant once the slope became flat.

Best of luck with your results though! :creep:

Uh yeah, terminal V is when the speed becomes constant.. Speed increases as the ball falls down but reaches a maximum, constant velocity at X...

And yeah, good luck to you aswell!

EDIT: AHEM, yeah nothing to do with terminal V, but I meant it reaches a maximum V which is constant :P (which is pretty much the same thing, minus the free falling object thingyz.)

(edited 11 years ago)

Reply 982

username973061

Original post by jqian

I think it won't be accepted sorry :frown:

. But you never know.

I put Weight due to gravity, is that okay do you think? :smile:

Reply 983

anuradha_d

1

Original post by mmss

To end this phase difference question if they did ask for the exact phase difference they would have given us space to work it out so clearly putting anti phase then phase is correct.... Right?

I thought it was relationship.If they wanted a numerical answer, they wouldve put a smaller answer space with working out space, not a line like this
..........................................................................

We arent expected to work out phase difference for 1 mark.

I just put out of phase for both.

Reply 984

Maphs

I am sooooo annoyed, for the springs in series and parallel i done it the other way round, i doubled series :angry:

Reply 985

Frodo Baggins

Original post by EmmaJane_

I got the same as you, I got 8.3
Is that definitely wrong?

Not that i know of, but all my friends didnt get it.

I did

a) 520 * 0.26=135.2

b) x * 0.63= (520 * 0.26) + (180 * 0.41)

c) 520 - (180 +331.7) = 8.3

Dont see how it is wrong but none of my friends got it.

Reply 986

jqian

1

Original post by adam17

I put Weight due to gravity, is that okay do you think? :smile:

That should be fine. I wish I have a single exam where I don't make a stupid mistake. Our teacher told us about polarisation with the TV serials 1 hour before the exam and I forgot it during the exam. :s-smilie:

Reply 987

internet tough guy

13

Apparently in the june 2009 paper, 120ums = 70 raw marks :eek:

how difficult/easy do you guys think this paper was compared to that?

Reply 988

anuradha_d

1

OKAY SO....

For the narrower core q, i wrote that the light ismore likelyto undergo total internal reflection as it is more likely to incident at an angle greater than the critical angle, (more parallel etc) so you wont lose as much data.

?

Reply 989

Frodo Baggins

Original post by Maphs

I am sooooo annoyed, for the springs in series and parallel i done it the other way round, i doubled series :angry:

Thats right tho mate!

Series-doubled
Parallel-halved

Reply 990

anuradha_d

1

Original post by Frodo Baggins

Not that i know of, but all my friends didnt get it.

I did

a) 520 * 0.26=135.2

b) x * 0.63= (520 * 0.26) + (180 * 0.41)

c) 520 - (180 +331.7) = 8.3

Dont see how it is wrong but none of my friends got it.

Check your working out :/ that doesnt seem right! No one i know got that...sorreh :/

Hope it works out

Reply 991

cooldudeman

18

a)i. Two Vectors
Force, velocity, acceleration, displacement etc.
ii. Two Scalars
Mass, distance, speed, energy etc.
b)Two forces on the helicopter
Air resistance
Weight
c)Triangle of forces means no resultant force, so in
equilibrium, so has no acceleration.
d)Weight=Fsinx
Can't remember the force or angle.

2a)GPE to KE from A to B, then KE back to GPE from
B to C. No energy lost due to friction/air
resistance, so mgh=0.5mv^2
b)Curve with decreasing gradient, then becomes
straight from B onwards.
c)Object remains at constant speed, because it is
acted on by no forces, and hence no resultant
force so no acceleration.

3a) Moment=Fd, in Nm
b)
c)
for the acceleration, i got 1.2, then the one after, i divided the weight by 9.81, then used f=ma

4a) Cladding
b) critical angle, just use formula
c) I did 180-30-85=65
d) Use n1sini=n2sinr
e) Multipath dispersion, pulse merging, loss of
information.

copy and add!!

Reply 992

jqian

1

Original post by internet tough guy

Apparently in the june 2009 paper, 120ums = 70 raw marks :eek:

how difficult/easy do you guys think this paper was compared to that?

I found that most of the calculations in the first half were straight forward. The hardest question in the first half I felt was the Galileo's experiment with the second slope. The average acceleration question- I was sure you had to use suvat but now I'm having my doubts. The spring question clearly has caused some controversy as the debate in this forum continues! The last question was quite difficult. Also, the phase relationship seemed to catch a few people out. So, all in all, this paper was probably only just slightly easier than June 2009. And, remember that an easier paper doesn't necessary high grade boundaries. I guess it also depends on the overall intelligence of the entire year group.

Reply 993

anuradha_d

1

Original post by Frodo Baggins

Thats right tho mate!

Series-doubled
Parallel-halved

Naww series is 1/k1+1/k2=1/ktotal

Parallel is k1+k2=ktotal

Reply 994

Little Wing

9

Original post by Frodo Baggins

Thats right tho mate!

Series-doubled
Parallel-halved

No it's not..
Series = halved
Parallel = doubled.

Reply 995

fayled

9

Original post by Frodo Baggins

Not that i know of, but all my friends didnt get it.

I did

a) 520 * 0.26=135.2

b) x * 0.63= (520 * 0.26) + (180 * 0.41)

c) 520 - (180 +331.7) = 8.3

Dont see how it is wrong but none of my friends got it.

For part b) shouldn't it be x * 0.63 + (180 * 0.41) = (520 * 0.26)
as the leg forces were both anticlockwise

Reply 996

username973061

Original post by jqian

That should be fine. I wish I have a single exam where I don't make a stupid mistake. Our teacher told us about polarisation with the TV serials 1 hour before the exam and I forgot it during the exam. :s-smilie:

ahhh thats annoying :/ that part wasn't worth many marks though I don't think.

Reply 997

rugito

for the moments question.... if I got part (a) wrong ... will I still get all the marks for (b) and (c) if i used the right methods but got (a) wrong?????
And I can't believe the answer to part (a) was soooo simple.... I spent most of my exam trying to figure out how to do it lol.

Reply 998

GSB

Original post by fayled

For part b) shouldn't it be x * 0.63 + (180 * 0.41) = (520 * 0.26)
as the leg forces were both anticlockwise

I realized it should have been that but didn't have time to change it so I ended up with 320 and 8 as well :frown:

Would I get any marks for it?

Reply 999

jqian

1

Original post by rugito

for the moments question.... if I got part (a) wrong ... will I still get all the marks for (b) and (c) if i used the right methods but got (a) wrong?????
And I can't believe the answer to part (a) was soooo simple.... I spent most of my exam trying to figure out how to do it lol.

You will get ecf marks yes. Everyone feels the pressure during the exams, the most simplest question can seem impossible. For example, in the total internal reflection one, you know how they gave you one of the angles of the triangle as 30 degrees? I was thinking for 10 minutes how to work out the value of i, after 10 minutes I realised the second angle was also 85 degrees (due to reflection) and the last angle was just 180-85-30!

AQA AS Physics A Unit 2 25/05/12 - PHYA2

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