OCR B (Advancing Physics) G492, 25th May 2012 Afternoon

Hmm. The piledriver question: for b), I think I calculated the work done on the pile by the weight as: (1.2+0.85)*2100*g; then divided this by 0.85 in c) to calculate the average force. Does that sound about right? can't remember the question :/

Edit: Nevermind; it was a 'show that' question, and the answer yield 42kJ, so I think it's right :smile:

(edited 11 years ago)

Reply 190

username937760

I thought that was a very nice paper; it had plenty of questions where you had to "show" something, which are always good as you know if you've got them right or wrong. It also had a fair bit of Maths (i.e. the roundabout question). That said, I know a lot of people in my 6th form hated it and the grade boundaries will likely be quite low.

Also, a shout-out on question 3, to whomever posted it earlier:

The answers were B, C, D. V = F x Lambda, therefore F = V/Lambda so the answer was Y = K/X, so C is the correct answer, not A.

Reply 191

username937760

Original post by tallguitarist

did anyone else remember getting the accelerations as -2.34 horizontally and -6.43 vertically? thanks, thought it was a good paper overall though

I got my X-acceleration as -2 and Y-acceleration as -5, with both answers to the nearest integers. To one decimal place they were -1.8 and -4.8, respectively.

Reply 192

Original post by tallguitarist

did anyone else remember getting the accelerations as -2.34 horizontally and -6.43 vertically? thanks, thought it was a good paper overall though

No, but I can tell you those are definitely not right:

Initially, car is travelling 12 m/s horizontally to the right; i.e. 0 m/s vertical and +12 m/s horizontal.

After 1.6 seconds, the horizontal component is 12cos(40); the vertical component is -12sin(40).

So horizontal acceleration is (12cos(40)-12)/1.6)=-1.8 m/s^2;
Vertical acceleration is (-12sin(40)-0)/1.6=-4.8 m/s^2.

Reply 193

When you see it...

OP

Original post by mathsguy

Predicted boundaries:

150UMS- 84
A-72
B-64
C-57
D-49
E-42

dunno what everyone thinks :smile:

Those grade boundaries can't exist! If it is 72 for an A and 64 for a B, then the UMS cap must be:
72 + (72-64) * 2
which is 88!

Reply 194

tallguitarist

Original post by Joel R

No, but I can tell you those are definitely not right:

Initially, car is travelling 12 m/s horizontally to the right; i.e. 0 m/s vertical and +12 m/s horizontal.

After 1.6 seconds, the horizontal component is 12cos(40); the vertical component is -12sin(40).

So horizontal acceleration is (12cos(40)-12)/1.6)=-1.8 m/s^2;
Vertical acceleration is (-12sin(40)-0)/1.6=-4.8 m/s^2.

**** i read the question wrong, i did all that except divided by 1.2 instead of 1.6... aghh, u think thats only one mark lost if i showed what i was doing clearly?

(edited 11 years ago)

Reply 195

When you see it...

OP

BTW since everyone seems to feel bad about this exam, I shall make you feel better by telling you about the mistakes I made!
For estimating the mass of a human, I put the highest value which iirc was 1000 kg! I wasn't thinking lol.
On the question where you had to equate g.p.e. and k.e. to find the relationship between v and g.p.e. I worked it out correctly but then got the x and y mixed up so got the wrong answer (can someone confirm - which was g.p.e. and which was speed?).
I got the entire microwave question wrong (10 - 11 marks!) because I thought they created a standing wave.
I left loads of questions 'mostly done', promising myself that I would get back to them at the end, but I only had 10 minutes left at the end so I couldn't go back to 'dot the is and cross the ts' so I reckon I lost up to 10 marks that way.
I guessed much of section C as I didn't know what they were looking for.
I made so many mistakes I can't even remembe them all! Overall, I think I lost at least 30 mars.
I do have some suggestions (which I am pretty confident in) for the roundabout an hammer questions if anyone wants me to post them (I disagree with much of what has been posted so far about these questions).
BTW most people in my colleg walked out the exam saying it was easy! I found it to be my worst exam since GCSE German! I hope I don't have to drop physics because of this. My unit 1 was pretty bad too but thankfully I got 29/30 for the coursework so that could save me.

Reply 196

kmjgirl

Original post by asif1995malik

I remember getting 5311 kgm-3 for the mean of the 6 results that I think was right...

I got that. well something was recurring and you kno how the exam board loves their significant figures :frown:

Reply 197

Original post by tallguitarist

**** i read the question wrong, i did all that except divided by 1.2 instead of 1.6... aghh, u think thats only one mark lost if i showed what i was doing clearly?

I'd say so: mark schemes usually deduct one mark for 'misread' or 'slip'.

Reply 198

Apocalyptic Fish

1

Very little mechanics, not good :frown:

I answered every one, but I think I made a silly error on the pile driver question.

Reply 199