AQA Physics PHYA4 - Thursday 11th June 2015 [Exam Discussion Thread]

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what sort of theory do you think is likely to come up about SHM?

Are we expected to derive the equations in the written paper for SHM

You don't need to derive equations.

Theory could explain energy transfer, phase differences, resonance, effects of damping on oscillations etc.

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Reply 2341

AR_95

Original post by CD223

You don't need to derive equations.

Theory could explain energy transfer, phase differences, resonance, effects of damping on oscillations etc.

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Ah, so glad we don't have to derive them.

I'm confident with energy transfer, resonance, and the effects of damping, but the idea of "phase difference" has always been one of my weaknesses in maths and now physics. I've never been able to get my head around it :redface:

If another question comes up about 2 oscillating objects with a difference of e.g 0.1s, I'm just gonna attempt to multiply the difference by the smaller time etc and that's when they're next in phase right. Hope that will work lmao

Reply 2342

CD223

Original post by AR_95

Erm, you'd divide the difference by the smaller period.

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Reply 2343

000alex

Original post by CD223

Erm, you'd divide the difference by the smaller period.

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Are we supposed to know an equation for phase difference?

Reply 2344

CD223

Original post by 000alex

Are we supposed to know an equation for phase difference?

Nope. Just that phase differences can vary sinusoidally so two oscillators can be anywhere between 0 and

2 \pi

radians out of phase.

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Thank you so much!

Original post by Mai.H

Thank you so much!

No worries - hope that helps clear it up :smile:

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Reply 2347

IWantSomeMushu

What do you guys think about only doing the packs of questions for the old spec PHYA4 unit and maybe only 1 or 2 current spec papers?

Reply 2348

CD223

Original post by IWantSomeMushu

What do you guys think about only doing the packs of questions for the old spec PHYA4 unit and maybe only 1 or 2 current spec papers?

I'd say it's best to do it the other way around really.

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Reply 2349

IWantSomeMushu

Original post by CD223

I'd say it's best to do it the other way around really.

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Wouldn't doing the packs strengthen your understanding in each sub-topic so then you could tackle a real paper much easier?

Reply 2350

CD223

Original post by IWantSomeMushu

Wouldn't doing the packs strengthen your understanding in each sub-topic so then you could tackle a real paper much easier?

Whatever seems best for you then - I'd just definitely get used to the latest style of questions if I were you.

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Reply 2351

Lau14

Original post by IWantSomeMushu

Wouldn't doing the packs strengthen your understanding in each sub-topic so then you could tackle a real paper much easier?

Half of doing papers at A level is knowing the format of the papers and understanding what will actually get you the marks. So yes, doing harder things to improve your understanding will help, but only if you also do enough actual papers to know what they want.

Reply 2352

IWantSomeMushu

Original post by CD223

Whatever seems best for you then - I'd just definitely get used to the latest style of questions if I were you.

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Original post by Lau14

I'll try to incorporate both techniques then.

Thanks!

Reply 2353

CD223

How much detail are we expected to know for the derivation of the acceleration of SHM?

Do we need to know to compare

(2 \pi f)^2

- \frac{k}{m}

and

- \frac{g}{l}

for masses on springs and simple pendulums?

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Reply 2354

gcsestuff

Original post by IWantSomeMushu

What do you guys think about only doing the packs of questions for the old spec PHYA4 unit and maybe only 1 or 2 current spec papers?

I'd say do both, do them in order and you will rattle though them in no time. I think you could do 01-09 in a day :smile:

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Reply 2355

gcsestuff

Original post by CD223

How much detail are we expected to know for the derivation of the acceleration of SHM?

Do we need to know to compare

(2 \pi f)^2

- \frac{k}{m}

and

- \frac{g}{l}

for masses on springs and simple pendulums?

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Don't know if this is linked, but In the old spec there are quite a few questions linking shm of a pendulum to the grav constant on earth

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Reply 2356

CD223

Original post by gcsestuff

Don't know if this is linked, but In the old spec there are quite a few questions linking shm of a pendulum to the grav constant on earth

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Well the period of the pendulum depends on g - is this what you mean?

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Reply 2357

Absent Agent

There seems to be some synoptic units that are not on the web. If you haven't access to them i can upload them on here

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Reply 2358

CD223

Original post by Mehrdad jafari

There seems to be some synoptic units that are not on the web. If you haven't access to them i can upload them on here

How do you mean, sorry? Anything that might help is welcome on the thread!

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Reply 2359

Absent Agent

Original post by CD223

How do you mean, sorry? Anything that might help is welcome on the thread!

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No, because i wasn't sure if you have access to them as they are not available on the AQA website. In don't have access to a PC right now but i will upload them tomorrow right after I've finished my exam :smile:

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