AQA A2 Mathematics MM2B Mechanics 2 - Monday 22nd June 2015 [Exam Discussion Thread]

OP

Original post by 221loki

Oh that makes so much sense thank you!! :smile:

So what would happen if it's right in the middle of the circle?

In that case it's only the reaction which provides the centripetal force as the weight is perpendicular meaning no component of the weight acts radially.

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Reply 321

Original post by CD223

In that case it's only the reaction which provides the centripetal force as the weight is perpendicular meaning no component of the weight acts radially.

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Oooh okay thank you!! :smile:

Reply 322

OP

Original post by 221loki

Oooh okay thank you!! :smile:

No worries! How prepared do you feel ahead of Monday? Not sure how many more past papers to do :s-smilie:

Reply 323

FeelsToWaltz

2

Original post by 221loki

Oh that makes so much sense thank you!! :smile:

So what would happen if it's right in the middle of the circle?

It should just be R = mv^2/a right at the middle because the weight acts perpendicular to the centripetal force :smile:

Reply 324

Original post by CD223

No worries! How prepared do you feel ahead of Monday? Not sure how many more past papers to do :s-smilie:

I don't feel prepared to be honest I keep forgetting the basics and I've been putting off mechanics it's my worst exam I'm hoping for a similar paper to the 2014 one which was surprisingly more straightforward than any other past paper since like 2011

I'm trying to go as far back as 2005 but I'm also trying to do the madasmaths booklets as well so hoping that'll be enough

Reply 325

Original post by FeelsToWaltz

It should just be R = mv^2/a right at the middle because the weight acts perpendicular to the centripetal force :smile:

Okay thank you!! :smile:

Reply 326

OP

Do people know of any papers I could attempt once I've done all AQA ones!?

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Reply 327

Original post by CD223

Do people know of any papers I could attempt once I've done all AQA ones!?

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You could try ocr or edexcel Solomon papers but I don't think they're as challenging as aqa
Maybe try madasmaths.com some of the questions are good use the maths booklets :smile:

Reply 328

OP

Original post by 221loki

You could try ocr or edexcel Solomon papers but I don't think they're as challenging as aqa
Maybe try madasmaths.com some of the questions are good use the maths booklets :smile:

Oh cool, thanks!

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Reply 329

Original post by CD223

Oh cool, thanks!

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No problem :smile:

Reply 330

Fluffehadam

1

Could someone explain June 14 8)b) to me. The mark scheme is confusing.

It seems to state that
ΔGPE + WD = ΔEPE

But I always thought the method was:
Initial Energy - WD = Final Energy.

These two statements seems to contradict themselves?

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(edited 8 years ago)

Reply 331

Tiwa

7

Anybody have tips for answering EPE questions?

(edited 8 years ago)

Reply 332

OP

Original post by Fluffehadam

Could someone explain June 14 8)b) to me. The mark scheme is confusing.

It seems to state that
ΔGPE + WD = ΔEPE

But I always thought the method was:
Initial Energy - WD = Final Energy.

These two statements seems to contradict themselves?

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Does this make sense?

ImageUploadedByStudent Room1434749259.171291.jpg

Reply 333

Shadez

Original post by Fluffehadam

Could someone explain June 14 8)b) to me. The mark scheme is confusing.

It seems to state that
ΔGPE + WD = ΔEPE

But I always thought the method was:
Initial Energy - WD = Final Energy.

These two statements seems to contradict themselves?

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there is no change in GPE if you take C to be the point with no GPE and so the so conserving energy would be:

Initial EPE = GPE + Final EPE + WD

ΔEPE=GPE + WD

Reply 334

OP

Original post by Tiwa

Anybody have tips for answering EPE questions?

Always write down the energy of a body before and after the movement. Also, always draw a sketch, it helps so much with determining what the extension should be represented as when forming quadratics.

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Reply 335

tripleseven

7

Original post by smilejensmile

Can somebody please help me with part b? I really don't understand :frown:

Is this the right answer for this? I feel like I've done something wrong... Sorry for my extremely poor hand writing, rushed it a bit since I'm tired but wanted to give it a shot :/

(edited 8 years ago)

Reply 336

Shadez

Original post by tripleseven

Is this the right answer for this? I feel like I've done something wrong... Sorry for my extremely poor hand writing, rushed it a bit since I'm tired but wanted to give it a shot :/

I believe that's correct :smile:

Reply 337

OP

Original post by tripleseven

Is this the right answer for this? I feel like I've done something wrong... Sorry for my extremely poor hand writing, rushed it a bit since I'm tired but wanted to give it a shot :/

Haha, we all know the feeling buddy - so tired after all these exams :frown:

Anyway, that's correct :smile: