OCR M2 - 18th June 2010

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I think that was Ok except I may have made a few arithmetic errors. Also, the last question could be done in many different ways, I just hope mine is valid.

Reply 41

AnythingButChardonnay

I really struggled with the last part of Q5 and with most of Q6. How could you even get a value for (queer w) when everything is in terms of T and l?

And I hope I was alright for the aeroplane question to just treat it normally (as one would a car). I didn't really know how to apply to information that the force was perpendicular to the motion... how else would it move? It wasn't a bloody helicopter.

Reply 42

Paddles

Mr MMMMMMMM??? :smile:

Reply 43

Peajay13

For the last question, did anyone else say that it wouldn't hit the roof??

Reply 44

ktc10

yeaahh .. it didnt hit the roof!!

Reply 45

ktc10

what did any1 get for w, when you had the equation T=.... and l=0.8m??

ktc10 - I got 4.16

And for the last part of q6, did anyone get A moving at U/5 in the opposite direction that it was originally travelling in and B moving at 3U/5 in the original direction of A??

Reply 48

synoxis

Peajay13 - Exactly what I got.

Reply 49

Peajay13

synoxis

ktc10 - I got 4.16

I got 2.68rad/s

Reply 50

synoxis

uh oh. We need Mr M to settle this.

Reply 51

Peajay13

synoxis

uh oh. We need Mr M to settle this.

Yep, did you assume that as it was just in contact with the slope, there was no reaction force??

Reply 52

synoxis

That i did.
(squarerroot(2)/2)T+(squarerroot(2)/2)R=mg

Put R=0
(squarerroot(2)/2)T=mg

Put in the 'show that' equation and solved.
Put back into the equation to make sure it was right. What did u do?

Reply 53

insertusername

Peajay13

And for the last part of q6, did anyone get A moving at U/5 in the opposite direction that it was originally travelling in and B moving at 3U/5 in the original direction of A??

i got this =), i also got w=4.16 however so who knows...

it was weirdly easy other than 5 and 7 and that was mainly because i am incapable of typing into a calculator correctly, once i finally typed them in right they worked fine. I have to say i'm very much a fan of the 17 mark question 6

I also got it didn't hit the roof for the last one so hopefully i've done alright

Reply 54

Peajay13

synoxis

I did the same thing as you but i've probably made an error somewhere.

Reply 55

jetheridge1

Lovely paper!...waiting for Mr M now...loads of show that ones just what you need :smile:

Reply 56

simoncb

My answers:

1) 15.8ms-1, cant remember angle
2) 9 degrees
3) 900N, 0.0275ms-2
4) 36N (36 point something), 58 degrees from horizontal
5) 4.16rads-1
6) u/5 and 3u/5 away from each other
7) doesnt hit roof, because when ball is level with C, it would have an x displacement of 4.92m, but for it to hit the roof, x must be less than or equals to 4.33m

Confirm anyone?

Reply 57

insertusername

jetheridge1

Lovely paper!...waiting for Mr M now...loads of show that ones just what you need :smile:

haha i know we like show that questions.....particularly when there are 20 marks worth of them

Reply 58

jetheridge1

Got all except acc for 3 ii) i got 0.549 ms_2 :frown:

Reply 59

Peajay13

Here are my answers:

1) 15.7 m/s, 63.4 degrees below horizontal

2) ii) 9 degrees

3) i) 900N
ii) 0.275 m/s^2

4) i) 32.6N
ii) 21.5N, 31.2 degrees anticlockwise from vertical

5) ii) 2.68 rad/s (this is most likely wrong...should be 4 something)

6) i) 2u/5
iv) A: U/5 in opposite direction to the original direction of A
B: 3U/5 in the original direction of A

7) ii) no