Author Topic: ALL CIE PHYSICS DOUBTS HERE !!!  (Read 172189 times)

Offline wstrawberries

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Re: ALL CIE PHYSICS DOUBTS HERE !!!
« Reply #765 on: June 06, 2011, 10:37:43 pm »
Question 9:-( I just need a confirmation on this )
Since the mass is going up and down..
At A its halfway going up..
At B its at its highest point...
At C its halfway going down..
And finally At D its at the bottom which is the lowest point of its motion..

Question 33:
Find the Pd of the resistors accross XQY or XPY..
The voltage across the 2 parallel wires is the same i.e 12 V...
To find the voltage of the 500 ohm resistor its 500/(500+1000) x12 = 4 V
ANd the voltage across the 2000 ohm resistor is 2000/(2000+1000) = 8 V
-->Therefore The potential DIFFERENCE is 8-4 volts = 4volts..
* you could also go using XQY and find the voltages accross the 1000 oh resistors and you will find the top one to be 4 and the bottom on eot be 8 so THe P.d between XandY is 4 volts...

@Ghost I forgot it too ;D
Glad to help :)

Thanks a lot :D uhhmm for q 33 what formula are you using to calculate 4V and 8V?

Offline SkyPilotage

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Re: ALL CIE PHYSICS DOUBTS HERE !!!
« Reply #766 on: June 06, 2011, 11:05:18 pm »
Thanks a lot :D uhhmm for q 33 what formula are you using to calculate 4V and 8V?
I used it as A ratio..But If you are confused...
USE the formula R=V/I..
For example the current passing through X is v/R= 12/1500 = 0.008 A
To find the V in the 1000 ohm resistor : 0.008 x 1000 = 8 V...
Through Y : do the same thing..
I= 12/3000 = 0.004 A
V in 1000 ohm resistor= 0.004 x 1000=4 volts..

Offline wstrawberries

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Re: ALL CIE PHYSICS DOUBTS HERE !!!
« Reply #767 on: June 06, 2011, 11:44:03 pm »
I used it as A ratio..But If you are confused...
USE the formula R=V/I..
For example the current passing through X is v/R= 12/1500 = 0.008 A
To find the V in the 1000 ohm resistor : 0.008 x 1000 = 8 V...
Through Y : do the same thing..
I= 12/3000 = 0.004 A
V in 1000 ohm resistor= 0.004 x 1000=4 volts..

ohhhh okay :) thanks again!

Offline username

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Re: ALL CIE PHYSICS DOUBTS HERE !!!
« Reply #768 on: June 07, 2011, 07:24:34 am »
qp11
7.  I have trouble in this too. How does horizontal component of velocity decrease to zero? Isn't it constant in a projectile?
8. It goes up 5m, comes down 3m. Displacement = 5-3 = 2m
9. v^2 = u^2 +2as
   s = v^2-u^2 / 2a
   v = 0, so 0 = u^2+2as -> 2a = -u^2/s or -u^2/x

Now, the new u = U+0.2u = 1.2u
V = 0
so s = 0-1.44u^2 /2a
s = -1.44u^2/(-u^2/x) = 1.44x
11. M1V1 -M2V2 = 0
    M1V1 = M2V2
V1/V2 = M2/M1
B
15. It can be either A or D (because they are closed vector triangles)
It's D, because the direction of the arrow representing the force by the cable is correct.
22. The length of the wire doesnt affect the extension. The load and cross-sectional area do. Here both are the same. So extensions of
     both the wires are same (1.5 and 2), that's y total e = 1.5 + 2 = 3.5mm

29. It's upward because electrons are attracted towards +ve plate. And ofcourse, it's not a part of the circle because the path is not exactly an arc.
40. Count th4e no. of protons in Argon, it's 18. Only option with 18 protons for argon is C. So C it is

qp12

9. There's a little bit of guess work involved here.
Given it's inelastic, the rebound velocity won't be v. Say, 40% of energy is lost, say around 0.6v
Change = (-0.6v*2m) - 2mv = -3.2mv
SO the change is almost 3mv.
(Even if u take 0.7v, u won't get 4mv+)

34. When x = 0, the voltage measured is across the whole of the wire, so it has to be V.
    when x decreases, and the pointer is moved at the right end of the part with resistivity p, the voltage is divided into 2 parts (p and 2p+3p)
   So the voltage across the length x is now, not V, but a lil less than V because some VOltage is lost in the remaining length of the wire.
Answer: B (note the graph is not a straight line because as x decreases, the resistance doesn't decrease proportionately)

13. Ofcourse it's D, gravitational pull is constant (mg). Mass is constant and a is a constant.
37. Check 1/R = 1/R1 + 1/R2 + 1/R3
And see when u get value of R as 50.




sry...
i got the links jumbled up:(

Offline EMO123

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Re: ALL CIE PHYSICS DOUBTS HERE !!!
« Reply #769 on: June 07, 2011, 07:27:00 am »
sry...
i got the links jumbled up:(
so you got that or not
if not then tell i will post all in another method

Offline physichemaths

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Re: ALL CIE PHYSICS DOUBTS HERE !!!
« Reply #770 on: June 07, 2011, 07:46:16 am »
I have trouble with question 24 june 2008? Anyone?

Offline username

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Re: ALL CIE PHYSICS DOUBTS HERE !!!
« Reply #771 on: June 07, 2011, 07:47:11 am »
so you got that or not
if not then tell i will post all in another method

umm
i mean u answered the rong questions
http://www.xtremepapers.me/CIE/International%20A%20And%20AS%20Level/9702%20-%20Physics/9702_w10_qp_11.pdf
questions: 9,13,34,37
http://www.xtremepapers.me/CIE/International%20A%20And%20AS%20Level/9702%20-%20Physics/9702_w10_qp_12.pdf
questions: 7,8,9,11,15,22,26,27,29,40

got it mixed up:(
« Last Edit: June 07, 2011, 08:49:15 am by username »

Offline physichemaths

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Re: ALL CIE PHYSICS DOUBTS HERE !!!
« Reply #772 on: June 07, 2011, 07:59:56 am »
I have trouble with question 24 june 2008? Anyone?
please help me :(

Offline username

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Re: ALL CIE PHYSICS DOUBTS HERE !!!
« Reply #773 on: June 07, 2011, 08:00:57 am »
please help me :(
answer is c
because
same steel so young modulus is the same

Offline physichemaths

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Re: ALL CIE PHYSICS DOUBTS HERE !!!
« Reply #774 on: June 07, 2011, 08:08:35 am »
answer is c
because
same steel so young modulus is the same
thanks! How about ques 26?

Offline physichemaths

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Re: ALL CIE PHYSICS DOUBTS HERE !!!
« Reply #775 on: June 07, 2011, 08:08:42 am »
answer is c
because
same steel so young modulus is the same

Offline physichemaths

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Re: ALL CIE PHYSICS DOUBTS HERE !!!
« Reply #776 on: June 07, 2011, 08:08:50 am »
answer is c
because
same steel so young modulus is the same

Offline Ghost Of Highbury

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Re: ALL CIE PHYSICS DOUBTS HERE !!!
« Reply #777 on: June 07, 2011, 08:30:36 am »
umm
i mean u answered the rong questions
http://www.xtremepapers.me/CIE/International%20A%20And%20AS%20Level/9702%20-%20Physics/9702_w10_qp_11.pdf
questions: 9,13,34,37
http://www.xtremepapers.me/CIE/International%20A%20And%20AS%20Level/9702%20-%20Physics/9702_w10_qp_12.pdf
questions: 7,8,9,11,15,22,29,40

got it mixed up:(

Oh darn!

@physichemaths - 26) Ip = k1/r^2
                               Ip = k2*A^2
k1/r^2 = k2*(8*10^-6)^2

Iq = k1/4r^2

Iq = k1/4r^2 = k1/r^2 * 1/4 = k2*(8*10^-6)^2 *1/4 = 1.6*10^-11k2
Iq = k2A^2
A^2 = 1.6*10^-11
A = sqrt(1.6*10^-11) = 4*10^-6
divine intervention!

Offline username

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Re: ALL CIE PHYSICS DOUBTS HERE !!!
« Reply #778 on: June 07, 2011, 08:40:26 am »
Oh darn!

@physichemaths - 26) Ip = k1/r^2
                               Ip = k2*A^2
k1/r^2 = k2*(8*10^-6)^2

Iq = k1/4r^2

Iq = k1/4r^2 = k1/r^2 * 1/4 = k2*(8*10^-6)^2 *1/4 = 1.6*10^-11k2
Iq = k2A^2
A^2 = 1.6*10^-11
A = sqrt(1.6*10^-11) = 4*10^-6
sry bout dat...

Offline physichemaths

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Re: ALL CIE PHYSICS DOUBTS HERE !!!
« Reply #779 on: June 07, 2011, 09:03:07 am »
sry bout dat...
how come the amplitude is times 2?