CIE PHYSICS P4 QUESTIONS

[falafail]

DO NOT POST ANYTHING HERE EXCEPT QUESTIONS RELATED TO PHYSICS PAPER 4 OR I WILL MURDER YOU 

okay, so:

1) june 02 Q 4b
2) nov 05 Q 4b  in the markscheme it says "endpoints of line correctly labelled" what are we supposed to label exactly???
3) june 06 Q 4c
4) nov 02 Q 1a how do we do (i)? and for (ii) why do we use 7 minutes and not 9?
5) june 04 Q 2b(ii) and for Q6 the last row is like + + 0, but shouldn't it have been 0 + -, 'cause the particles move so they're doing work??
6) june 06 Q 2b(ii)
7) how do you determine the amplitude from a ke/pe graph?

HELP

[AndrewCedric]

1) The EP graph NEVER GOES NEGATIVE. So A t=0 it is max.. At t= 0.025 approx, it is 0.. It reaches Max again at at t=0.05

2)Label The maximum and minimum displacement.

3)Max Speed--> Horizontal ( right / left ) part of the circle          Max Accel--> The uppermost vertical part of circle

4) Use the formula Power x Time ( 2min ) = mass x specific heat x ( 100 - 20)
FOr part 2, We use 7, cause only at that time the water starts boiling. Only for the last 7 min that the temperature is constant. So we can apply Q=mL

5)Use formula p=1/3 (density) ( Mean square speed )
NO. FOr the box thing. THERE IS NO WORK DONE. W=pdV. No change in volume. So no work done.
We know Q must be +.. SO leaving U must be +. Alternatively, working from U. No change in Temperature. But Their state changes, thus their EP increases. REMEMBER THIS IS NOT IDEAL GAS, SO EP CANNOT BE NEGLECTED.

6)Use pV=nRT for the balloon too. And Compare No of moles with part a.

7) KE/PE graph against what?? Usually we do displacement. So, Just look for the Max EP and down to the x axis. Thats the amplitude.

HOPE IT HELPS!!!!!

[ifraha18]

cn someoen xlain the graph of q7 part 1 june 2005.??

[Onion]

cn someoen xlain the graph of q7 part 1 june 2005.??

Half-life is the time for undecayed atoms to be reduced by half. So the graph would be an exponential growth, starting from origin. At t = 2.6, mass of Fe-56 would be 1/2(1.4) = 0.7 micrograms

Mass of Fe-56 would increase over time, so at another 2.6  hours (t = 5.2), mass = (0.7) + 1/2(0.7) = 1.05 micrograms and so on ...

[ifraha18]

Thanks...

[falafail]

1) The EP graph NEVER GOES NEGATIVE. So A t=0 it is max.. At t= 0.025 approx, it is 0.. It reaches Max again at at t=0.05

2)Label The maximum and minimum displacement.

3)Max Speed--> Horizontal ( right / left ) part of the circle          Max Accel--> The uppermost vertical part of circle

4) Use the formula Power x Time ( 2min ) = mass x specific heat x ( 100 - 20)
FOr part 2, We use 7, cause only at that time the water starts boiling. Only for the last 7 min that the temperature is constant. So we can apply Q=mL

5)Use formula p=1/3 (density) ( Mean square speed )
NO. FOr the box thing. THERE IS NO WORK DONE. W=pdV. No change in volume. So no work done.
We know Q must be +.. SO leaving U must be +. Alternatively, working from U. No change in Temperature. But Their state changes, thus their EP increases. REMEMBER THIS IS NOT IDEAL GAS, SO EP CANNOT BE NEGLECTED.

6)Use pV=nRT for the balloon too. And Compare No of moles with part a.

7) KE/PE graph against what?? Usually we do displacement. So, Just look for the Max EP and down to the x axis. Thats the amplitude.

HOPE IT HELPS!!!!!

THANK YOUU

but...
2) where exactly are those?
3) why? explain please.
6) that's what i did but i got it wrong could you work it out?

[AndrewCedric]

2) Both ends of your line graphs.

3) Max Speed happens when displacement=0. All of the Ep is converted to Ek when d=0. And thats when the pivot is at the horizontal part.
Max Accel. happens when Ep= max. When displacement=max too. Because a=- (omega)^2 . (displacement)
Accel is then directly but in opp. direction to displacement. 

6)Sorry. I was careless before. Here is the right way==
volume of gas at 1.85 × 10^5 Pa  = (2.5 × 10 × 4.00 × 10 ) / (1.85 × 10)
    = 5.41 × 10 ^6 cm^3
 
  5.41 x 10^6= 4x10^4+(7.24 x 10^3)(N)
N= 740

The method which was wrong, is that we assume both cases (in cylinder and balloon) have the same pressure. But they do not. You must get 747 at the beginning. AFter doing this type of question, its very assuring to do it by another method aside pV=nRT.. Say p1v1=p2v2 and so on.

[falafail]

3) Max Speed happens when displacement=0. All of the Ep is converted to Ek when d=0. And thats when the pivot is at the horizontal part.
Max Accel. happens when Ep= max. When displacement=max too. Because a=- (omega)^2 . (displacement)
Accel is then directly but in opp. direction to displacement.  

but why is it when the pivot is at the horizontal part?

also, i have more questions

8 ) why are values of gravitational potential near to an isolated mass all negative?
9) nov 03 Q 1a
10) june 05 Q 5b
11) how does a capacitor store energy?
12) june 05 Q 6b all of it -_-
13) nov 05 Q 5b (ii) 1 and 6c (ii)
14) june 06 Q 6c  and 8b (ii)
15) specimen paper Q 3b (i) 1 + (ii) 2
16) june 02 Q 6 a
17) june 04 Q 5d (ii) why is it 3??
18) nov 06 Q 6b + c (iii) and 7b

i know they're a lot, sorry

[falafail]

oh also, are we supposed to know the specifics about nuclear fusion and fission, and probing matter??

[AndrewCedric]

AHHHHH SO MANYYYYYYY
AHAHAHAHHA

Add me at msn and i will try my best to help.

When the pivot is at the horizontal part the bar thing is halfway up and halfway down. so, displacement=0.
 

[falafail]

AHHHHH SO MANYYYYYYY
AHAHAHAHHA

Add me at msn and i will try my best to help.

When the pivot is at the horizontal part the bar thing is halfway up and halfway down. so, displacement=0.
 

alright, what's your msn?

[AndrewCedric]

bruce_lee_gibb@yahoo.com

[falafail]

bruce_lee_gibb@yahoo.com

um, i added you and it was like, "two seperate accounts found for this person" o.O

[MaNi_DaDuDe]

um, i added you and it was like, "two seperate accounts found for this person" o.O

falaFAIL, you're stealing my study buddy.

[falafail]

falaFAIL, you're stealing my study buddy.

orly? is he any good?