IGCSE/GCSE/O & A Level/IB/University Student Forum

Qualification => Subject Doubts => GCE AS & A2 Level => Math => Topic started by: nid404 on October 16, 2010, 06:18:59 am

Title: M1 OCR
Post by: nid404 on October 16, 2010, 06:18:59 am
 the 2nd part of the attached question, I dunno why I am not confident abt my answer. I don't have the mark scheme, so I want to confirm my answer with you guys.

I get P as 13.2 N...If someone could verify the answer, it would be great  :)
Title: Re: M1 OCR
Post by: elemis on October 16, 2010, 06:31:45 am
I'll do it.
Title: Re: M1 OCR
Post by: elemis on October 16, 2010, 06:36:57 am
Is coefficient of friction 0.5 ? Did you get that ?
Title: Re: M1 OCR
Post by: nid404 on October 16, 2010, 06:37:35 am
Is coefficient of friction 0.5 ? Did you get that ?

yup
Title: Re: M1 OCR
Post by: elemis on October 16, 2010, 06:42:33 am
Okay, I think your answer is wrong.

This is what I did for the last part.

R - Pcos60 - 3g = 0

hence, R = Pcos60 + 3g

Next, Pcos30 - 0.5(Pcos60 + 3g) = 0

Hence P = 23.9 N
Title: Re: M1 OCR
Post by: elemis on October 16, 2010, 06:43:26 am
I did this in a hurry as I have to go for breakfast. Tell me if you think I'm right/wrong.
Title: Re: M1 OCR
Post by: nid404 on October 16, 2010, 06:48:22 am
Oh yes

R will be the sum of 3g and Pcos 60.

I took R as 3g-Pcos60 I didn't see the direction of the force. My bad.

Thanks  ;)
Title: Re: M1 OCR
Post by: elemis on October 16, 2010, 06:58:15 am
No worries.

I find it easier if you draw a set of axis and draw in the force vectors.

Title: Re: M1 OCR
Post by: nid404 on October 16, 2010, 07:14:14 am
I feel lazy :P And end up making silly mistakes  >:(

Okay I want to cross check my answers for this one too. Just post the answers. If they differ, then you need to take the pains to type the whole thing :P, else not  ;D

Take your time  ::)





Title: Re: M1 OCR
Post by: elemis on October 16, 2010, 07:15:25 am
Did you read my PM ?

Which year is this from ?
Title: Re: M1 OCR
Post by: elemis on October 16, 2010, 07:16:46 am
I'm on it.
Title: Re: M1 OCR
Post by: nid404 on October 16, 2010, 07:18:13 am
Did you read my PM ?

Which year is this from ?


Yeah I replied...check check!!

June 2005 M1
Title: Re: M1 OCR
Post by: elemis on October 16, 2010, 07:19:57 am
http://www.xtremepapers.net/OCR/Maths/2005%20Jun/L_A_Level_Maths_MS_Jun_05.pdf (http://www.xtremepapers.net/OCR/Maths/2005%20Jun/L_A_Level_Maths_MS_Jun_05.pdf)
Title: Re: M1 OCR
Post by: nid404 on October 16, 2010, 07:41:01 am
I got them right :D

Thanks  ;D
Title: Re: M1 OCR
Post by: nid404 on October 16, 2010, 07:51:34 am
By the way it was jan...i got the ms for it  ;D thanks for the ocr directory...I should ask astar to upload them on FEP too
Title: Re: M1 OCR
Post by: elemis on October 16, 2010, 08:07:03 am
Congo ;) Glad you've got the MS now. Yeah. We should have them on FEP.
Title: Re: M1 OCR
Post by: nid404 on October 17, 2010, 07:50:34 am
the 4th part...I don't really understand what they're asking for :S

Title: Re: M1 OCR
Post by: Deadly_king on October 17, 2010, 08:32:35 am
the 4th part...I don't really understand what they're asking for :S



When A strikes the ground, B continues to rise against gravity until it reaches its maximum point where v = 0. Then B starts to descend due to its weight. String becomes taut again when B reaches the level it started to rise against gravity, i.e at the time when A touched the ground earlier.

In other words, you need to find the time taken the particle B takes to reach its maximum height as from when A strikes the ground. Multiply it by 2 since for the string to become taut again, B covers twice this distance(once upwards and then downwards) and during the same time.

For the required solution you need to add the value you obtain to your answer in part(ii)  :D
Hope it helps :)

If you still cannot do it, let me know ;)
Title: Re: M1 OCR
Post by: nid404 on October 17, 2010, 03:44:09 pm
When A strikes the ground, B continues to rise against gravity until it reaches its maximum point where v = 0. Then B starts to descend due to its weight. String becomes taut again when B reaches the level it started to rise against gravity, i.e at the time when A touched the ground earlier.

In other words, you need to find the time taken the particle B takes to reach its maximum height as from when A strikes the ground. Multiply it by 2 since for the string to become taut again, B covers twice this distance(once upwards and then downwards) and during the same time.

For the required solution you need to add the value you obtain to your answer in part(ii)  :D
Hope it helps :)

If you still cannot do it, let me know ;)

Ah I got it :D Thank youu  ;D