Edexcel Mathematics: Mechanics M3 6679 01 - 17 May 2017 [Exam Discussion]

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http://pmt.physicsandmathstutor.com/download/Maths/A-level/M3/Papers-Edexcel/January%202003%20MS%20-%20M3%20Edexcel.pdf

Can someone help me with 3b please. Not sure why d=r .

Had trouble uploading the image so sorry about that.

I understand it now!!!

(edited 6 years ago)

Reply 221

Major-fury

Original post by dididid

unless stated to give to a degree of accuracy , I'm pretty sure you can leave as a fraction with g .

it depends on where its held at rest, if its at rest at a point after the equilibrium extension then T>particles Weight therefore will move upwards towards equilibrium and if where its held at rest is before the equilibrium point then T<particles weight and therefore will move downwards towards equilibrium. if thats what you're asking?

In june 2013 (R) the particle is on the right hand side of the equilibrium and so I thought since we'd be moving to the left ( towards equilibrium) we would resolve in that way / that would be our x increasing. However we are meant to do the opposite for some reason.

Reply 222

dididid

Original post by Major-fury

you can do it either way tbh. i.e using Ta-Tb=-ma (as its moving towards origin and taking away from origin as =+ve) or Tb-Ta=ma which is the same but multiplied by -1.

Reply 223

saira.p

Can anyone help me understand example 19 chapter 5? Does anyone have tips on doing moments?

Reply 224

TSRUser12345

Original post by TrueDAN

I was surpised with some of them - id actually recommend doing atleast a couple of them!

Which would you recommend? I have done the last two and they seem easier than past papers

Reply 225

Major-fury

Original post by dididid

you can do it either way tbh. i.e using Ta-Tb=-ma (as its moving towards origin and taking away from origin as =+ve) or Tb-Ta=ma which is the same but multiplied by -1.

what do you mean by 'as its moving towards origin and taking away from origin as = +ve ' ?

Reply 226

dididid

Original post by Major-fury

what do you mean by 'as its moving towards origin and taking away from origin as = +ve ' ?

taking acceleration to the right as positive and is in the example you mentioned Ta>Tb so moves in direction of Ta which is to the left and hence the acceleration will be to the left which is negative. if that makes sense

Reply 227

coco98

Original post by TrueDAN

Ah okay thank you mate - that proof one is pretty insane - ive just memorised how
madasmaths did it just in case it comes up, cheers

Can you please send me the link for madasmaths proof, as i'm trying to learn them!

Reply 228

TrueDAN

Original post by coco98

Can you please send me the link for madasmaths proof, as i'm trying to learn them!

Scroll down to the c.o.m by calculus part :biggrin:

http://www.madasmaths.com/archive/maths_booklets/mechanics/m3_centre_of_mass.pdf

Reply 229

TrueDAN

Original post by TSRUser12345

Which would you recommend? I have done the last two and they seem easier than past papers

I found them to be about the same as papers - guess it is different for everyone. I enjoyed paper D because it had a really nice gravitational problem on the moon and a good COM question that has came up before.

Reply 230

dididid

Original post by TrueDAN

Scroll down to the c.o.m by calculus part :biggrin:

http://www.madasmaths.com/archive/maths_booklets/mechanics/m3_centre_of_mass.pdf

why am i only just seeing these madasmaths booklets now lol, they're well good.

Reply 231

TrueDAN

Original post by dididid

why am i only just seeing these madasmaths booklets now lol, they're well good.

Yup he also literally predicts some of the exact questions - some papers have basically replicas of some of his problems - Ive finished pretty much all his booklets for M3 and they have helped a ton - hes my favourite source for all of maths/ furthermaths and I really like how he sets out his solutions. Enjoy ploughing through some of his questions haha! His circular motion one was very very good as well

Reply 232

dididid

Original post by TrueDAN

haha yh I'm just reading through some questions that i generally struggle with, does he have a prediction for tomorrows M3 paper. thanks for posting will defy be using for the rest of my exams.

Reply 233

coco98

Original post by TrueDAN

Though, wouldn't you say the madasmath's booklets are mainly of a higher difficulty than most questions that come up on the edexcel papers?

Reply 234

TrueDAN

Original post by coco98

Though, wouldn't you say the madasmath's booklets are mainly of a higher difficulty than most questions that come up on the edexcel papers?

I thought so - but then you see questions almost identical appear so I think it is best to alteast cover a few - but yes, some questions are just insane haha

Reply 235

TrueDAN

Original post by dididid

haha yh I'm just reading through some questions that i generally struggle with, does he have a prediction for tomorrows M3 paper. thanks for posting will defy be using for the rest of my exams.

No worries - yeah definitely do. Not sure he does, sorry! But we never know with what edexcel are like so it is too hard to tell :/

Reply 236

dididid

Original post by AAls

could you please explain it to me? i don't know how d=r as i know the c of mass has to lie within the hemisphere but why on the plane face?

Reply 237

dididid

Original post by TrueDAN

No worries - yeah definitely do. Not sure he does, sorry! But we never know with what edexcel are like so it is too hard to tell :/

ahh right yh fair enough lol, hope its a standard paper without any of those C of Mass in equilibrium questions where you have to resolve a million times or find a 100 different angles, always end up messing those up somehow.