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How did you find the M3 exam?

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Original post by TheFarmerLad
...


That was.. comprehensive :biggrin:
Original post by Student403
That was.. comprehensive :biggrin:


Fair play if you read all of it :wink:
Original post by ombtom
Ignoring simple mistakes, I might've got every answer apart from the 9 marker. When it's allowed, please would a genius post/send me a worked solution with how many marks for each step? :s-smilie:


Was the 9 marker the show question about AB> L/2 ?

If so, basically you had to set up a new circle with radius r, with the string projected from a horizontal position upwards at the speed you found in the previous question. Then, because it told you that it completed a semi circle, you know that the tension at the top would be >0. Then you can just set up the standard tension/energy equation for the particle at the top, set it >0, then rearrange and worked out that radius < L/2. Which meant that AB>L/2 (Because r=L-AB).

I think that's right!? I ended up with what it asked, so it hopefully is. :biggrin:
Reply 23
Avatar for ombtom
ombtom
17
Original post by Frannoooooooo
Was the 9 marker the show question about AB> L/2 ?

If so, basically you had to set up a new circle with radius r, with the string projected from a horizontal position upwards at the speed you found in the previous question. Then, because it told you that it completed a semi circle, you know that the tension at the top would be >0. Then you can just set up the standard tension/energy equation for the particle at the top, set it >0, then rearrange and worked out that radius < L/2. Which meant that AB>L/2 (Because r=L-AB).

I think that's right!? I ended up with what it asked, so it hopefully is. :biggrin:


Think I attempted an energy equation, and the wrote centripetal force, but for some reason I didn't find T when the particle was at the top of the circle. :angry:
Original post by ombtom
Think I attempted an energy equation, and the wrote centripetal force, but for some reason I didn't find T when the particle was at the top of the circle. :angry:


Well there'll definitely be some marks for that. It was a difficult question to be fair, I left it until the end because I didn't get it initially. I think that concept has only come up a couple of times in the past if I remember correctly??
Reply 25
Avatar for ombtom
ombtom
17
Original post by Frannoooooooo
Well there'll definitely be some marks for that. It was a difficult question to be fair, I left it until the end because I didn't get it initially. I think that concept has only come up a couple of times in the past if I remember correctly??


Yeah, unless I scribbled it out and wrote something stupid. :lol:
Reply 26
Avatar for dsefton
dsefton
1
How many marks am I likely to lose for saying T>0 rather than T>=0 for question 6b (show that AB>=l/2) given that all my other working was correct? Also am I likely to lose a mark as I put -1/3N for the 1st question and it apparently asked for the magnitude?
Original post by dsefton
How many marks am I likely to lose for saying T>0 rather than T>=0 for question 6b (show that AB>=l/2) given that all my other working was correct? Also am I likely to lose a mark as I put -1/3N for the 1st question and it apparently asked for the magnitude?

between 1 and 2 overall. you wont't lose more the 1 for each mistake and maybe lose nothing in the tension question but i think you will
Original post by dsefton
How many marks am I likely to lose for saying T>0 rather than T>=0 for question 6b (show that AB>=l/2) given that all my other working was correct? Also am I likely to lose a mark as I put -1/3N for the 1st question and it apparently asked for the magnitude?


I put >=, was this correct???
Original post by Louisb19
I put >=, was this correct???


Yep


Posted from TSR Mobile
Original post by TheFarmerLad
Easy compared to recent papers. Boundaries are going to be sky high and tight this year I reckon, 70 for 90ums at the very least imo

No they will be the same if not lower than last year, the last two questions had difficult parts and places you could easily make a mistake whereas all of 2015 was standard - don't think TSR is representative AT ALL of the over all population who take the exam. Well Done for finding it easy though but not everyone will have full marks like people seem to think on here
Reply 31
Avatar for ombtom
ombtom
17
Original post by Foutre en L'air
No they will be the same if not lower than last year, the last two questions had difficult parts and places you could easily make a mistake whereas all of 2015 was standard - don't think TSR is representative AT ALL of the over all population who take the exam. Well Done for finding it easy though but not everyone will have full marks like people seem to think on here


Hope so. There were only three other people doing M3 at my school, and they're all basically geniuses, so my perspective is probably distorted. :frown:
Original post by Foutre en L'air
No they will be the same if not lower than last year, the last two questions had difficult parts and places you could easily make a mistake whereas all of 2015 was standard - don't think TSR is representative AT ALL of the over all population who take the exam. Well Done for finding it easy though but not everyone will have full marks like people seem to think on here


Disagree, think the boundaries will be slightly higher. Many questions were very similar to ones found in recent papers and it is those recent papers that most candidates turn to first for their revision. Didn't say it was easy, just said that it was more straightforward compared to other papers
Reply 33
Avatar for dsefton
dsefton
1
Original post by physicsmaths
between 1 and 2 overall. you wont't lose more the 1 for each mistake and maybe lose nothing in the tension question but i think you will


Thanks, I thought I might have lost 2 for 6b as my working would've lead to AB>L/2 but I just changed this to AB>=L/2 right at the end of my working to satisfy the 'show that' :colondollar:

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