Year 12s: what will be the first way you research your future options? >>

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

Scroll to see replies

I'm stuck on question 5b from this exercise sheet:http://www.madasmaths.com/archive/maths_booklets/mechanics/m2_m3_elastic_strings_springs.pdf

The answer is 1.65m
Here's what I've done could someone point out where I went wrong

Attachment not found

Doesn't matter I've figured it out :smile:

Reply 361

samlyon

Can anyone try to explain question 5 from january 2012 please?
http://filestore.aqa.org.uk/subjects/AQA-MM2B-QP-JAN12.PDF

Edit: I read the question wrong, I thought it was going down a hill instead of around a bend :/

(edited 8 years ago)

Reply 362

sum1random

Original post by samlyon

Can anyone try to explain question 5 from january 2012 please?
http://filestore.aqa.org.uk/subjects/AQA-MM2B-QP-JAN12.PDF

Centripetal force in the case of the parcel is provided by friction cause surface is rough

f<=uR but for max speed, centripetal force is max so friction is max so

uR=mv^2/r

R=mg so

umg=mv^2/r

you can see the mass cancels so 'm' is not required

ug*r=v^2
v = root(ugr)

sub in the values and find v

(edited 8 years ago)

Reply 363

samlyon

Original post by sum1random

Thank you

Reply 364

Jetraft87

We wont lose marks for using column vectors as opposed to using the i and j format aren't we? Because i and j require so much more effort to work with than column vectors.

Reply 365

Lau14

Original post by Jetraft87

We wont lose marks for using column vectors as opposed to using the i and j format aren't we? Because i and j require so much more effort to work with than column vectors.

You shouldn't do, it means the same thing! My teacher recommends writing them out in the same format as the question for your final answer but I usually forget

Reply 366

JackNorman

Why are the grade boundaries for M2 so high 😩 I don't understand, it's quite a big step up from M1 in my opinions and the grade boundaries are so much higher

Reply 367

CD223

Original post by JackNorman

Why are the grade boundaries for M2 so high 😩 I don't understand, it's quite a big step up from M1 in my opinions and the grade boundaries are so much higher

It's a unit that a lot of people do as a further maths module. I'm doing it as part of normal maths A level as I did M1 last year, but the boundaries are always so high because generally the people who do it are insanely clever 👀

Posted from TSR Mobile

Reply 368

ike96

Can u explain 9c to me, please? I do not get where the cos 2theta come from.

Posted from TSR Mobile

Reply 369

CD223

Original post by ike96

Can u explain 9c to me, please? I do not get where the cos 2theta come from.

Posted from TSR Mobile

https://m.youtube.com/watch?v=kA4F-p5Hj_4

Posted from TSR Mobile

Reply 370

olatee

Hey can someone do question 9 part c june 2014 i dont understand how they got 2.04m

june 2013*

Original post by olatee

Hey can someone do question 9 part c june 2014 i dont understand how they got 2.04m

The extension was 2.5m initially but A has moved 0.46m, so the extension now is 2.5-0.46 = 2.04m. Using a quadratic where the distance travelled is defined to be x, the extension at x metres can be expressed as (2.04 - x).

Posted from TSR Mobile

Reply 373

Tiwa

For Jan 09 question 7b, how do they expect me to know the angle.....

Reply 374

ike96

Thanks for the video.

Posted from TSR Mobile

Reply 375

sum1random

Original post by Tiwa

For Jan 09 question 7b, how do they expect me to know the angle.....

Its a standard rule in vertical circles that when the object is in the below half of the circle the height it has gained is
=r-rcostheta

this is cause the angle the vertical line makes with the radius line at point B is theta as well (alternate angles)
where theta is the angle between radius at A and radius at B

so r-rostheta = 2m (height)

rearrange to get theta=60deg

(edited 8 years ago)

Reply 376

CD223

Can anyone quickly go over the rules needed for a complete circle in each situation?

Bead on a wire
Ball in a cylinder
Ball on a hill
Ball on a string

Posted from TSR Mobile