AQA Physics Unit 4 Thread - JAN 28th 2010 (Post Exam)

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i'm so screwed... have just starting revising, too late.

Anyway, i was doing those exam questions at the end of the chapter and there was a question on F=kx and E=1/2 k x^2 synoptic, ya but i didn't expect it to be that specific..
there's also a quantum physics question from unit 1, wth??

Reply 21

Robofish

futuredoc77

these A2 papers can be synoptic, meaning they can test us on anything that has been in the previous units as well as the current unit, i.e. stuff from unit 1 and 2 in AS

Reply 22

futuredoc77

Robofish

these A2 papers can be synoptic, meaning they can test us on anything that has been in the previous units as well as the current unit, i.e. stuff from unit 1 and 2 in AS

Yes, I AM aware of that. Its just that i didn't expect the synoptic part to be that specific, you know.
I thought it'll be like biology, where you get asked general stuff about enzymes and stuff... its not as specific as say "what is a peptide bond and how is it made?" which would be very specific and we shouldn't be expected to remember... you know what i am saying?

Reply 23

Robofish

futuredoc77

ye i know what you mean, the only things i can think of them asking is about hookes law in relation to springs in SHM or maybe internal resistance in capacitors

Reply 24

futuredoc77

Robofish

ye i know what you mean, the only things i can think of them asking is about hookes law in relation to springs in SHM or maybe internal resistance in capacitors

like I said, they have asked about an alpha decay in the "exam-style questions" in the book, lets hope none of that stuff pops up tomorrow.

the scariest synoptic for me would be diffraction and waves and all that crap.. i didn't even learn it properly last year... i hope it doesn't come back to bite me in the ass tomorrow.. :s-smilie:

Reply 25

futuredoc77

Also, how much time do you reckon we should spend on the multiple-choice questions, i mean its a third of the whole module, so... would 45 min be enough?

Reply 26

koki234

are grav field strength and potential gradient vectors or scalars? And can someone please explain how damping affects resonance as its in the spec but there's not much on it in the book. Thanks for any help!

Reply 27

Robofish

futuredoc77

Also, how much time do you reckon we should spend on the multiple-choice questions, i mean its a third of the whole module, so... would 45 min be enough?

yeah roughly about 45mins, but you might be able 2 get thru the mutli choice quicker hopefully spend more time on the written answers

Reply 28

Chriz M

koki234

You only get resonance with light damping. I think they are vectors but not certain, according to the holy source of reference (wikipedia) gravitational field strength is a vector pointing towards the centre of mass. With gravitational potential I think it is a vector as the gradient is g so should be a vector.

Reply 29

Ram92

futuredoc77

O there is a simple reason for that!
They are taken from old syllabus papers and they learned about waves fields and nuclear energy. The alpha decay comes from nuclear energy. However the spring constant you need to know!

Also hello robofish! look at the page before can you do the questions i cant understand? thanks vishal!

Reply 30

rbnphlp

what are the advantages and disadvantages of resonance

Reply 31

Robofish

Ram92

im doing that paper as we speak, except im stuck on Q6, i dunno how though..

Reply 32

Ram92

Robofish

im doing that paper as we speak, except im stuck on Q6, i dunno how though..

6 is B because... i cant remember how to do it! gimie a sec

When you get to the ones I can't do post them up :biggrin:

It is a good paper to do it will iron out those stupid mistakes! and there are some questions I have not seen before which is good if they come up now

Reply 33

Robofish

Ram92

6 is B because... i cant remember how to do it! gimie a sec

When you get to the ones I can't do post them up :biggrin:

It is a good paper to do it will iron out those stupid mistakes! and there are some questions I have not seen before which is good if they come up now

also got Q7 wrong, once again, dunno how..

Reply 34

Chriz M

rbnphlp

what are the advantages and disadvantages of resonance

That is a bit random. I guess the disadvantages are easier: Can cause large amplitudes in a vibrating system that can break a bridge, building, spring. Advantages? I guess making a large vibration for swings, mixing stuff, buzzers. I can't think of any really.

Reply 35

Ram92

Robofish

also got Q7 wrong, once again, dunno how..

7 is 18 - (-12) which is 30 then times that by the mass!
then you get the answer and you know it is going away from the racket

Reply 36

rbnphlp

Chriz M

That is a bit random. .

trust me AQA gets much more randomer
Im doing the old one , so just wanted to sneak in trying to revise..

Chriz M

Advantages? I guess making a large vibration for swings, mixing stuff, buzzers. I can't think of any really.

MRI SCAN , microwave ovens, musical instruments .
Your turn ask a question :smile:

Reply 37

Chriz M

rbnphlp

trust me AQA gets much more randomer
Im doing the old one , so just wanted to sneak in trying to revise..

MRI SCAN , microwave ovens, musical instruments .
Your turn ask a question :smile:

Thanks, I'm glad you mentioned that. And going on the infamous AQA Biology exam, I'm not holding my hopes high for a straight forward paper. In that case my question would be why does gravitational potential's formula have a negative sign?

Reply 38

rbnphlp

Chriz M

its the way how gravitational potential is defined..
"The work done in moving an object from infinity to the earth's surface"
the negative sign indicates that potential at infinity (zero) is higher than the potential on the earth.so
an abject at earth has negative potential eenrgy so work must be done on the object to lift it towards infinity.