How did PHYSICS P21 go?

[Maryum7]

How did physics A levels P21 go for you guys?
I didn't find it easy at all. I had confusions in many questions.
What was the answer for the first part of the last question though, the one about the quarks and +e charge of protons?

 

[mariacosta]

i think it went quite well overall, the last question of electricity where they put a cell in parallel really confused me though..

for the quark one you had to say that protons have a structure of uud, u=2/3e e and d=1/3e so proton=2/3e+2/3e-1/3e=1e
and then do the same for neutron which is udd=0

 

[Maryum7]

What did you do for the 2 force questions regarding the parachute? I was struggling.

I couldn't even complete those two parts. How did you work it out?

 

[Maryum7]

i think it went quite well overall, the last question of electricity where they put a cell in parallel really confused me though..

for the quark one you had to say that protons have a structure of uud, u=2/3e e and d=1/3e so proton=2/3e+2/3e-1/3e=1e
and then do the same for neutron which is udd=0

I never read about that 2/3e thing in the book. Sigh
Btw what was your answer to that base units question 1 part 1?

 

[Maryum7]

i think it went quite well overall, the last question of electricity where they put a cell in parallel really confused me though..

for the quark one you had to say that protons have a structure of uud, u=2/3e e and d=1/3e so proton=2/3e+2/3e-1/3e=1e
and then do the same for neutron which is udd=0

What did you do for the 2 force questions regarding the parachute? I was struggling.

Also, if you guys can recall the tricky parts from the question paper(as i have forgotten a lot of things), let me know and we can discuss and compare our answers

 

[ThePacifics]

The paper wasnt that easy.
It had its tricky parts.
Did u all write that the wave was coming towards the observer right?

 

[mariacosta]

What did you do for the 2 force questions regarding the parachute? I was struggling.

I couldn't even complete those two parts. How did you work it out?

Yeah those were tricky.. For the first part I basically said that the res. F=O vertically so the W+Tvertically=the upwards force and got 1050N
In the second you had already calculated the acceleration before so you knew what the resultant force was, and then you'd equal it to Thorizontally-R (don't remember the value i got)

 

[mariacosta]

I never read about that 2/3e thing in the book. Sigh
Btw what was your answer to that base units question 1 part 1?

That wasn't in mine either, lucky my physics teacher explained that and I think I've seen a few past papers with that questions..
I think it was kgm-1s-2

 

[mariacosta]

The paper wasnt that easy.
It had its tricky parts.
Did u all write that the wave was coming towards the observer right?

~

I wrote away because the frequecy observed was lower than the actual frequency of the wave...

 

[ThePacifics]

And what about that paraglider question? It was sorta tricky too and that lambda value?

 

[ThePacifics]

What might the grade threshold for this paper since the paper might have seemed easy but it was sorta tricky what say?

 

[Momal AR]

the paper had a lot of tricky questios

 

[Maryum7]

The paper wasnt that easy.
It had its tricky parts.
Did u all write that the wave was coming towards the observer right?

It wasn't too easy but it was way easier than the MJ 2016 paper, so the threshold probably won't be too low. I think it'll be in 40's for A. Maybe 45

 

[Maryum7]

And what about the current in B and the ratios?

Wasn't it the simple V=IR formula? Because it was just one mark. Im not sure about the ration though, i somehow got 2 and im sure it was wrong. What did you get

 

[ThePacifics]

Wasn't it the simple V=IR formula? Because it was just one mark. Im not sure about the ration though, i somehow got 2 and im sure it was wrong. What did you get

BTW the next one for the ratio it was of three marks so would we get 1/3 marks for writing the P= I square R formula right? even tho the final ans wasnt correct?

 

[Maryum7]

BTW the next one for the ratio it was of three marks so would we get 1/3 marks for writing the P= I square R formula right? even tho the final ans wasnt correct?

Yeah there's always a mark for formulas

 

[Gwen Winchester]

~

I wrote away because the frequecy observed was lower than the actual frequency of the wave...

i also wrote away and ans was 37.7 it wasnt negative though.IT WAS "AWAY FROM OBSERVER" RIGHT???
cuz frequency was lower than the original means source is moving away