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Author Topic: ALL CIE PHYSICS DOUBTS HERE !!!  (Read 176936 times)

Offline da_rockstar

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Re: ALL CIE PHYSICS DOUBTS HERE !!!
« Reply #540 on: April 27, 2011, 01:57:40 pm »
Can anyone help june 2008 paper 4. question 6.
please explain with reasoning the answers to part (a) and (b).
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Offline astarmathsandphysics

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Re: ALL CIE PHYSICS DOUBTS HERE !!!
« Reply #541 on: April 27, 2011, 02:15:24 pm »
a) perpendicular since F=BIlsin x where x is angle between perpendicular to coil and magnetic field
force max when x=90
b)i)torqu=force*distance
2.1*10^-3 =F*0.028 so F=0.075N


ii)0 since parallel to field

c)F=BIlN
0.075=B*0.170*4.5*140
B=0.07T
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Offline HUSH1994

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Re: ALL CIE PHYSICS DOUBTS HERE !!!
« Reply #542 on: April 27, 2011, 02:36:32 pm »
ON 2003 P1 Q11
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Offline da_rockstar

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Re: ALL CIE PHYSICS DOUBTS HERE !!!
« Reply #543 on: April 27, 2011, 03:53:30 pm »
astarmathsandphysics....i agree with what you said for part (a) but the thing is that in the mark scheme they say parallel..........
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Offline Vin

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Re: ALL CIE PHYSICS DOUBTS HERE !!!
« Reply #544 on: April 27, 2011, 05:16:08 pm »
Quote from: ~~!$!HUSH!$!~~ on April 27, 2011, 02:36:32 pm
ON 2003 P1 Q11

Initial momentum = mu
Final momentum = - mu
( why u, because the speed remains unchanged, however direction changes, here it is perpendicularly opposite therefore velocity -ve. Agreed?)

Change in momentum = Final m. - Initial m.
= (- mu) - (mu)
= -2mu
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Offline HUSH1994

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Re: ALL CIE PHYSICS DOUBTS HERE !!!
« Reply #545 on: April 27, 2011, 06:08:01 pm »
Oh thanks man :)
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Offline Vin

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Re: ALL CIE PHYSICS DOUBTS HERE !!!
« Reply #546 on: April 27, 2011, 07:51:48 pm »
Quote from: ~~!$!HUSH!$!~~ on April 25, 2011, 05:39:19 pm
each of the 3 resistors has 5 K(ohms),and the potential differnce across the circuit is 2 volts,so each resistor will get 2/3V(the six of them as they are connected in parallel)and the V at X is 4/3(as you have 2 resistors before)and 2/3 at Y,so 4/3 - 2/3 = 2/3.

Im not really good at explaining but i hope you get it

Oh yes, gave me a great idea. Thanks a lot! ;)
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Offline HUSH1994

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Re: ALL CIE PHYSICS DOUBTS HERE !!!
« Reply #547 on: April 28, 2011, 03:52:55 am »
Anytime ;)
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Offline HUSH1994

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Re: ALL CIE PHYSICS DOUBTS HERE !!!
« Reply #548 on: April 29, 2011, 05:07:51 am »
MJ 2004 P1 Q9
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Offline astarmathsandphysics

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Re: ALL CIE PHYSICS DOUBTS HERE !!!
« Reply #549 on: April 29, 2011, 08:03:17 am »
error in ms?
Junn 04 p1 q9

Use suvat vertically to find t
s=1.25
u=0
v=
a=9.8
t=
s=ut+1/2at^2
1.25=0+1/2*4.9t^2 so t=0.505s

horizontal speed constant so use distance =speed*time
10=s*0.505 so speed=19.8 D
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Offline HUSH1994

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Re: ALL CIE PHYSICS DOUBTS HERE !!!
« Reply #550 on: April 29, 2011, 01:37:38 pm »
I get it thanks man :)
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Offline physichemaths

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Re: ALL CIE PHYSICS DOUBTS HERE !!!
« Reply #551 on: April 30, 2011, 06:22:59 pm »
help me with november02 question 14 paper 1 mcq
« Last Edit: April 30, 2011, 06:25:34 pm by physichemaths »
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Offline SkyPilotage

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Re: ALL CIE PHYSICS DOUBTS HERE !!!
« Reply #552 on: April 30, 2011, 06:53:34 pm »
Quote from: physichemaths on April 30, 2011, 06:22:59 pm
help me with november02 question 14 paper 1 mcq
For the rule to be in equilibrium, clockwisew moments = anticlockwise moments
Taking moments about the pivot at 40 cm mark:
  - Clockwise moments = (0.1kg x 10) x 0.1 m = 0.10 Nm          *P.s: since the rule is uniform, the centre of gravity is on the 50 cm mark
  - Anticlockwise moments = (0.02kg x 10) x 0.6 m = 0.12 Nm
Therefore we know that the 50 g mass must be hanged to the right of the pivot, hence :
CLockwise moments  = 0.1 + 0.5x(distance from pivot)=0.12 ---> 0.5 x (d)=0.12 Nm --> d=0.04 m= 4 cm to the right of the pivot!
Therefore the 50 g mass must be suspended at the (40 + 4) cm mark= 44cm which is C!
I hope you got it! tried to make the explanation as simple as possible :)
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Offline SkyPilotage

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Re: ALL CIE PHYSICS DOUBTS HERE !!!
« Reply #553 on: April 30, 2011, 06:58:57 pm »
-Can someone tell me how the percentage uncertainity determines the number of significant figures???
A simple question on this was on June 2003 Question 5...
-And on paper 3 practicals, can we use a FO and calculate c from the eqn by substitution?
WHen do use s.f and d.p in our table of results?
Thanks ...
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Offline SkyPilotage

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Re: ALL CIE PHYSICS DOUBTS HERE !!!
« Reply #554 on: May 03, 2011, 10:17:03 am »
Anyone?   ???
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