* Physics HL 2011 * HL predictions / discussion / aftermath * (1 thread only please)

Gyaradose

Aoifums wrote: »

What I said (may or may not be right. I made it all up) <, >, ^, v being the directions of the forces. Merry-go-round was going right (>)
The force of the merry-go-round beneath the child. >
Gravity pushing down, v
The force of the merry-go-round acting up on the child ^
Air resistance <
Friction <
and I think I put one more.

I just put in friction, i assumed weight, reaction and air reseistance would be redundant

LilMissCiara

Gyaradose wrote: »

I just put in friction, i assumed weight, reaction and air reseistance would be redundant

They are still acting on him though. Fair enough they cancel but they are still there!

Aoifums

I drew the ****est diagram of all time >_< I needed to make it look as if I knew what I was doing.

Gyaradose

LilMissCiara wrote: »

They are still acting on him though. Fair enough they cancel but they are still there!

Well the question was relative to motion in a circle, so i only put in forces relative to that

LilMissCiara

Aoifums wrote: »

I drew the ****est diagram of all time >_< I needed to make it look as if I knew what I was doing.

My child was a circle.. My roundabout thing was a wonky oval..! :P

Aoifums

LilMissCiara wrote: »

My child was a circle.. My roundabout thing was a wonky oval..! :P

Leave obese children out of this!!
Mine was a stick. A stick in a skort.

Geog ariphic

Sparticle wrote: »

Q7 was a bit iffy.
Did anyone else say radiation( by infrared from cup)(Solved by the colour white) and conduction with cup (Solved by insulating material) for Q7 b?

Yup, well said all 3 and just thought up stuff..

Did anyone else create an elaborate two beakers, two calibrated thermometers and one thermocouple set-up for Q7c?
I think they're right in theory but do you think I'll get any marks for them?

Well ya but the whole set up was the thermocouple, you didnt need another one in there..but you needed the voltmeter (to measure emf).

Gyaradose wrote: »

6000 newtons i think

Really? I got about 200.... something small anyway.
Anyone mind confirming this one?

jumpguy wrote: »

For "describe how the reading on the detector may vary" I just went on about how the thickness of the paper may vary thus that means the amount of beta radiation hitting the detector will vary with the thickness of the paper and etc.

Ya that's exactly it, that's all they wanted.

cabbage kid

Quote:
Originally Posted by Gyaradose
6000 newtons i think

Really? I got about 200.... something small anyway.
Anyone mind confirming this one?

I don't know about confirming it but I got 6000N as well

LilMissCiara

cabbage kid wrote: »

I don't know about confirming it but I got 6000N as well

Sounds familiar here as well!

BrendaN_f

cabbage kid wrote: »

I don't know about confirming it but I got 6000N as well

yep, got 6000 too.

equated kinetic energy to Fd (from w=fd)

Geog ariphic

cabbage kid wrote: »

I don't know about confirming it but I got 6000N as well

LilMissCiara wrote: »

Sounds familiar here as well!

BrendaN f wrote:

yep, got 6000 too.

equated kinetic energy to Fd (from w=fd)

I would click thanks on all of your posts for answering my question speedily precisely, but, you know......:(

Geog ariphic

Wow... was thinking of a completely different question. Sorry for wasting all y'all's time.
I should be banned for spamming

RP77

Gyaradose wrote: »

what will happen if there was no friction ( i put down the merry go round will rotate under him and he would remain stationary as a joke and answered it seriously too)

No friction means no centripetal force to keep him moving in a circle so the boy would move in the direction of the linear speed of the merry go round at that particular point. For an object moving in a circle its inear speed at any point lies in the direction of a tangent to the circle at that point I.e. He would move in a straight line. Hope this makes sense!

amortentia

BrendaN_f wrote: »

yep, got 6000 too.

equated kinetic energy to Fd (from w=fd)

Ugh I got 6000 first then thought it was wrong and changed it and got something like 12000

danoboy254

this was a pretty nice paper

can anyone vouch for these answers?

q4 the resistance (i got 1/slope) ans: 3.125 ohms

q7 0.01266 kg and 29.136 j/K

q9 in terms of F = 1.3F <<<<< killing me :P



and what kind of equation were they looking for in q10 (a) for the nucleus
was in the N=P+e or and actual element like Ra

irish_man

Geog ariphic wrote: »

Also, didnt answer the end of the 12 b at, only found out afterwards.

How did people get on with 12?

I did Q12 part a,b,c
A was tricky enough. I don't think I got the last bit right.
B was ok. I had seen it before.
C was very easy IMO.

i got 13.238 m^2 for the area part in b. Anyone get the same??

Geog ariphic

danoboy254 wrote: »

this was a pretty nice paper

can anyone vouch for these answers?

[...]

q7 0.01266 kg and 29.136 j/K

Yes!!!!! For me, aswell as for you:D

electrictrad

danoboy254 wrote: »

q9 in terms of F = 1.3F <<<<< killing me :P

Got 4F/3

Digits

danoboy254 wrote: »

this was a pretty nice paper

can anyone vouch for these answers?

q4 the resistance (i got 1/slope) ans: 3.125 ohms

q7 0.01266 kg and 29.136 j/K

q9 in terms of F = 1.3F <<<<< killing me :P



and what kind of equation were they looking for in q10 (a) for the nucleus
was in the N=P+e or and actual element like Ra

I got the same as you for q4 and q9. Didnt do q7 though.

Geog ariphic

electrictrad wrote: »

Got 4F/3

Is everyone forgetting to put newtons at the end of their answer, or just leaving it out for the sake of online brevity?

If the former, you're all gonna loose a mark for it! AHAHAHAHAHAHAHAHAHAAAAAAAHHHHAHAHAHAHA*cough, cough*
*horrible hacking cough. Victim falls to floor. Blood exits alimentary and repiratory canals via mouth, nose and ears. And they, since they were not the ones dead, turned to their affairs.*

stealinhorses

I wrote that Millikan was known for calculating the mass of the electron (which I remembered reading in my chemistry book). Any chance that they will accept charge or mass in the marking scheme? :P

Overall, I thought the paper was difficult in parts. I didn't get the final calculation in the particle physics question and tripped up on some other things, but it was OK in general.

The experiment questions were really handy though, as straight-forward as you will get.

electrictrad

cbaa wrote: »

does anyone know the answer to 5a, the force? i couldn't get it

6000N

electrictrad

Geog ariphic wrote: »

Is everyone forgetting to put newtons at the end of their answer, or just leaving it out for the sake of brevity?

If the former, your all gonna loose a mark for it! AHAHAHAHAHAHAHAHAHAAAAAAAHHHHAHAHAHAHA*cough, cough*
*horrible hacking cough. Victim falls to floor. Blood exits alimentary and repiratory canals via mouth, noose and ears. And they, since they were not the ones dead, turned to their affairs.*

. . .I actually wrote 4F/3 N. . .hopefully I won't lose any marks for not putting in my units on boards. . .

mcon1

Did anyone get a very small value for the Resistance of the copper wire in Q12c (.00675 ohms i think)??
The wording of the question confused me because they gave the power value in Watts per metre. I just used joules law p=(I squared)(R) to find the resistance

TommyMcG08

ye i did!! delighted sum1 else got that i thought i was just spoofing it ha

electrictrad

mcon1 wrote: »

Did anyone get a very small value for the Resistance of the copper wire in Q12c (.00675 ohms i think)??
The wording of the question confused me because they gave the power value in Watts per metre. I just used joules law p=(I squared)(R) to find the resistance

I got that. . . .to be more specific, I got 6.75 x 10^3 ohms

Got 1.79 x 10^-3 for wire diameter for part ii....

TommyMcG08

irish_man wrote: »

I did Q12 part a,b,c
A was tricky enough. I don't think I got the last bit right.
B was ok. I had seen it before.
C was very easy IMO.

i got 13.238 m^2 for the area part in b. Anyone get the same??

ye i got 13 sumting i thought that was i pretty cool question

magicianz

Geog ariphic wrote: »

Is everyone forgetting to put newtons at the end of their answer, or just leaving it out for the sake of brevity?

If the former, your all gonna loose a mark for it! AHAHAHAHAHAHAHAHAHAAAAAAAHHHHAHAHAHAHA*cough, cough*
*horrible hacking cough. Victim falls to floor. Blood exits alimentary and repiratory canals via mouth, noose and ears. And they, since they were not the ones dead, turned to their affairs.*

Actually since F is in newtons you dont have to put it in. The same as 10g is 98m/s^2

Digits

magicianz wrote: »

Actually since F is in newtons you dont have to put it in. The same as 10g is 98m/s^2

Yeah what he said. HAHAHAHAHAHAHAHAHAHAAAHHAHAAAAH!!!!!!11!1111!!! :pac:

Geog ariphic

magicianz wrote: »

Actually since F is in newtons you dont have to put it in. The same as 10g is 98m/s^2

Unfortunately, untrue.

F in this case is standing for some unknown constant (i think you'd call that a variable), however in the equation in the log tables it is a symbol, in which case units are implied.

If 'F' stood only for the concept of 'Force' then newtons would be implied. However, it is standing for some specific value of force, a number, therefore the units are required.

. . .I actually wrote 4F/3 N. . .hopefully I won't lose any marks for not putting in my units on boards. . .

Well you gave a second attempt, with the correct answer, and the corrector must give the marks for the best attempt.
So, i think you get away with it......just this once