Edexcel M2

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As further explanation of my previous statement:

"I've just had an unnerving thought. This question about the deflection, in retrospect, I think that 116.6 degrees is correct. If you imagine a baseballer/cricketer hitting a ball, it reverses direction and goes up. If it's original direction is 0 degrees, to reverse horizontal direction it has to deflect by >90 degrees."

I'd like to offer further expalanation, via diagram, of what I mean.

Reply 221

Firelight

yer its 52.16 F**************************** SH*****************

I divided by 50 insteaD OF f********* 60 sh***********************

Reply 222

Silly Sally

XYTER

yer its 52.16 F**************************** SH*****************

I divided by 50 insteaD OF f********* 60 sh***********************

Don't worry - most marks are for the method

Reply 223

mensandan

BossLady

well the ones that you're +ve about, then u can put those answers next to em, would be v helpful actually :smile:

.... as for the resistance one..... work out GPE at start. Then work out GPE andKE at end. Find the difference. Difference=Fd. Stick in relevant values to get F where F=R. This should give u 51/52N or something like that. Infact, is this how u did it? cuz if so, u probs just have a calculation error.

Correctamundo (I hope), I ended up with R = 52.16 N too, but rounded this to 3sf also in case they were gonna be fussy about that rounding stuff

Reply 224

Firelight

Crap that whats i freakin get for thinking i did well
Takes the piss a bit.

Reply 225

mensandan

SRKeates

This diagram shows a reversal in the direction of i which is not the case (it has gone from 30i to 10i, no reversal same direction), the ball would have carried on without interruption, it is this fact that tells you where to measure the angle from. You measure the angle from the path the ball would have taken without interference. However I must admit that this is a very unfortunate question as either solution would seem sensible depending on how you view the scenario.

Reply 226

ResidentEvil

do we always have to go through papers and answers? Let's just chill, and it's too tempting for me to click on this thread :mad:

Reply 227

SRKeates

mensandan

This diagram shows a reversal in the direction of i which is not the case, the ball would have carried on without interruption, it is this fact that tells you where to measure the angle from. You measure the angle from the path the ball would have taken without interference. However I must admit that this is a very unfortunate question as either solution would seem sensible depending on how you view the scenario.

Oh yes of course, what am I thinking of. The resulting velocity was 10i + 20j, allowing the ball to carry on in the same direction. I'm glad you've clarified that, I was worrying that I had lost some marks! I believe the examiner's report for this M2 paper will show, distinctively, an even spread amongst right and wrong answers with, as you stated, people coming to different conclusions depending on how they "imagined" the scenario.

Reply 228

Barny

mockel

where were the other marks?

I only got 0.4mg for P for ladder question, so thats 7 marks gone, I didnt do b and c of the restitution question, 6 marks, so thats 13 marks that I definately havent got. Now the 2 marks for the angle, 15 marks, and anything else I might of got wrong. (I think I got 25J lost or something? not 40). So Ive lost 15 marks at least :frown:

Reply 229

Barny

SRKeates

In that case its a shit situation, you shouldnt have to interpret a question.

Reply 230

SRKeates

imasillynarb

With 15 marks lost you're still holding on to an A!

Reply 231

mensandan

SRKeates

Glad to hear you had it the same way as me dude on the exam. I bet you are right when you say the mark scheme will show this confusion was rampant. I just hope we have got the right end of the stick and not made any silly errors.

Reply 232

mensandan

imasillynarb

I think you'll get 3/7 for getting the first inequality out, 3 more if you got the second and one for the complete inequality. So it looks like 3 marks there not zero dude.

Reply 233

Firelight

Well lar dee da you're on track for an A
You wont lose 7 marks for ladder you will lose 4
The energy question as long as you did a before and after subtraction u'll get 2
As for the restitution question unless u left if completely blank u'll drop 6 max
So lets re evaluate shall we 65/75 u can afford to lose 5 other marks somewhere SO DONT WORRY you still have strong chance for an A

Reply 234

Silly Sally

imasillynarb

Don't worry!!!! :smile:

LOADS of people only got that P was 0.4mg - most people didn't really see the other limits - and plus you wouldn't have lost all 7 marks -well at least i hope not cos i did the same as you :rolleyes:

!!! Plus i lost the 6 marks for the collisions, and plus i have probably made some really strange obscure mistakes - i am after all silly sally!!! :biggrin:

Also everyone always remembers their mistakes!!!

Reply 235

Barny

mensandan

I think you'll get 3/7 for getting the first inequality out, 3 more if you got the second and one for the complete inequality. So it looks like 3 marks there not zero dude.

I didnt put it as an inequality, just P = 0.4mg :smile:

I need 78% for an A overall, its gonna be close :frown:

Reply 236

vinz

there was this 8/9 year old girl doing alevel mechanics at my school today, group of 10-15 people from dunno where turned up outa nowhere to sit it. was running at the same time as my gcse stats so they sat at the opposite end of the hall, this 4ft little girl at the front. made a few heads turn as they left whilst we were still stats-ing away.

looks like you've got some competition from the bottom!

Reply 237

m:)ckel

imasillynarb

well, for the the ladder question, i only got 0.4mg, but there's no way we'll lose all 7 marks, probably just about 3 or 4, since we got half the inequality correct.
and for the kinetic energy, you may well get some method marks, so don't worry about it too much :smile:

Edit: just saw your other post...see my next post