AQA AS Physics Unit 2 (PHYA2) June 9th 2016 Resit paper

To have done it from the bank you would need a new resistive force from yhe rock because the boy adds weight downwards....it could have been done possibly but was much jarder that way

Reply 361

thatcooldude2.0

15

Original post by gasman95

Seen a few people here mention that the initial gradient of the truck (e.g. the acceleration)
would be greater. Surely, as the question stated that the water flowed out continuously across the entire journey, so therefore the initial mass would be the same and hence the same initial gradient as before.

Yep I put the line so that it started like the initial gradient then increased. Did you draw a line with gradient continuously increasing to the very end? I thought it said that the water will flow for all the time given on the graph

Reply 362

mbh16

2

Original post by micycle

This is how I drew it:

Oh damn! i did this, but i did a straight line coming out instead of it refracting

Reply 363

philo-jitsu

2

Original post by WillRose

absolutely horredous exam

for the 6 marker i said the speed would end up greater as fricton between the tyres and the road is proportional to the reaction force, less reaction, less friction, greater end speed

Yeah i put this also....dont see why its wrong it makes perfect sense

Reply 364

Nerrad

7

Also the question said that total resistive force is proportional to its mass, so decreasing mass means decreasing resistive force and since driving force is constant, driving force is then bigger than resistive force which causes it to accelerates. I then wrote eventually all the water flowed out and everything is back into equilibrium again

(edited 7 years ago)

Reply 365

Lychee628

19

Im depressed ffs :frown:

Reply 366

TSRPAV

7

swear the boy can stand on it? if you take moments about the end of the plank(one not on embankment) and do at a point of tilting around the rock senario the wieght of the plank and its distance from rock is grater than the wieght of the boy and his distance from rock so he can

Reply 367

Nerrad

7

Original post by mbh16

oh ok, but yeah the driving force is constant but the resultant force won't be cause of air resistance?

It said total resistive force, so I assumed they had air resistance included

Reply 368

mbh16

2

Original post by Billsonbubbles

Cheers !

I stated the CW and ACW moment and said that as the rock provided the CW moment and the ACW came from the boy and the weight of the plank the CW was larger hence he could not walk to the end

oh right, i said that he could but everyone that did it your way said he couldn't and everyone that worked out the moment about the rock said he could

Reply 369

JamesC98

I got exactly the same

Reply 370

Razzy1028

M

Posted from TSR Mobile

Reply 371

mbh16

2

Original post by Nerrad

It said total resistive force, so I assumed they had air resistance included

oh right ok so how did u draw the graph?, cause it said that u could use the graph to explain

Reply 372

Xela22

1

It was ok, just had problems with time management, they really wanted to **** us hard :smile:

Reply 373

thatcooldude2.0

15

What did you guys get for the max vertical height in the projectile motion question?

Reply 374

GdotMdot

5

First time I've ever not finished an exam. I finish every phya2 paper I've done as revision 10 minutes early at least, this one I had to rush the last two questions (my strongest topics) and had to guess with no calculations the light in diamond diagram. Will be lower than 48 for an A judging by the comments on here. Assuming that we're stronger students than the average based on the fact that we care enough to look up the exam before and after, I'm going to say roughly 45 for an A, wouldn't be lower than 43 though I assume because 42 would be 60% and it is a bit ridiculous to say 60% for an A. I'm very strong on phya2 but I'd be surprised if I get over 50 marks, probably 46ish. I luckily revised centre of mass and Vx=Vcos(feta) as I had a strong suspicion they'd come up with it being last exam, and them not coming up before I believe, but I was very dumbfounded at the spring, and projectile questions because they were so different, and the 6 marker was definitely something I dropped serious marks on. Spent 10 minutes on it at least, probably more and only have got 4 marks max, probably 2-3. But as the old AQA motto goes, "Fail to prepare, prepare to fail. Prepare, prepare to fail."

Reply 375

tomhiggins7

Original post by gasman95

Seen a few people here mention that the initial gradient of the truck (e.g. the acceleration)
would be greater. Surely, as the question stated that the water flowed out continuously across the entire journey, so therefore the initial mass would be the same and hence the same initial gradient as before.

yeah i put the initial gradient as the same, but said the the acceleration would continue increasing for a longer period, and my sketch on the graph had the same initial gradient and stayed steeper than the other gradient for longer, until it reached a constant velocity, a bit higher up than the lorry without the leak.

Reply 376

Rahmada

The embankment one:

R (Reaction force at embankment) = 0
Resolve from the rock.
Vertical force at the left much be greater than the right for the boy to stand without falling

Mass of boy = 46kg Distance to boy = 0.8
Mass of plank = 40kg Distance to C.O.M = 1.2

46g * 0.8 = 40g * 1.2 + C
313.6 = 361 + C
C is negative so the boy can stand.

That's how I did it.

Reply 377

Nerrad

7

Original post by mbh16

oh right ok so how did u draw the graph?, cause it said that u could use the graph to explain

It said you can draw ON the graph, not draw a graph haha. So I drew a dotted line between when the gradient is increasing and when the gradient is 0. Then labelled resistive force=driving force and resistive force < driving force. Hope I'm right

Reply 378

GdotMdot

5

Original post by philo-jitsu

What were the other questions for the velocity one...

It was 5ms up and sin25....rearrange to get 11.83

Then i think one question was how high it travvelled which was done using suvat and i got 1.27m up or 1.3m rounded.

Another was horizontal distance travveled which was done by pythagorus of 11.83^2 -5^2 and sqroot to find horizontal speed....then times by flight time of 1.3s which gets s=13.9m

The diamonds ones i sped through so need help remembering....the second material had a higher refractive index...bare with

Considering a human is 1.8mish I think it would be higher than that, but I'm probably just saying that to make me convinced my 13m answer was right.

Reply 379

WillRose

2

Original post by TSRPAV

swear the boy can stand on it? if you take moments about the end of the plank(one not on embankment) and do at a point of tilting around the rock senario the wieght of the plank and its distance from rock is grater than the wieght of the boy and his distance from rock so he can

Took moments about the rock to find out the maximum mass that can be put on before tilting (when reaction at the bank = 0)

That mass was 48kg

46<48 therefore he can stand without tilting

AQA AS Physics Unit 2 (PHYA2) June 9th 2016 Resit paper

Quick Reply

Related discussions

Latest

Trending

Trending

Articles for you