Author Topic: physics  (Read 18001 times)

Offline ruby92

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Re: physics
« Reply #90 on: April 26, 2010, 08:16:59 pm »
M/j 2003 paper1
34,40,18,30,35

Offline ruby92

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Re: physics
« Reply #91 on: April 26, 2010, 10:03:51 pm »
o/n 2003 paper 1
12,7(why isnt it A how is it B?arent we supposed to find the gradient?)and 37,16

Offline astarmathsandphysics

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Re: physics
« Reply #92 on: April 26, 2010, 10:09:59 pm »
34.0 to 7,5 cos 0 to 5/6 of resistaNCE can be between P and Q
30.D since 2*2/3 -1/3 =1 charges must add up to 1
18.D since KE is propritional to v^2 F=Energy =braking force*distance=1/2mv^2
30.average current =(100+20)/2=60mA
charge=It=60mA*8=480mC
45. E is uniform between paralell plates

Offline astarmathsandphysics

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Re: physics
« Reply #93 on: April 26, 2010, 10:12:56 pm »
7 C horizontal acceleration is 0 so horizontal vel is constant=ucos alpha
apply v=u+at vertically
12. 8*2+2*4=6v v=4

Offline ruby92

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Re: physics
« Reply #94 on: April 27, 2010, 08:05:10 pm »
2.why not A? how do we know the direction of the resultant force?
could you please explain Q's 15 and 35 in more detail

Also o/n 2002 paper 1; 36

no 12(o/n 2003)  ??? ???

Offline astarmathsandphysics

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Re: physics
« Reply #95 on: April 27, 2010, 08:16:22 pm »
which paper

Offline ruby92

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Re: physics
« Reply #96 on: April 27, 2010, 09:36:21 pm »
m/j 2002 paper 1

Offline ruby92

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Re: physics
« Reply #97 on: April 27, 2010, 11:01:39 pm »
M/j 2004 paper 1
8 (why D why not C)
9
31(why D and why not C)

O/N 2004 paper 1
20, 18,11,31,33,26.

« Last Edit: April 27, 2010, 11:14:03 pm by ruby92 »

Offline astarmathsandphysics

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Re: physics
« Reply #98 on: April 28, 2010, 08:54:17 am »
can you post question and paper and year in same post
mj 2004 p1 q8 D - as ball speeds up acc falls as air resistance increases]

9. Work vertically s=ut+1/2at^2 u=0 cos he vertically speed is zero
1.25=0+1/2*10*t^2
t=0.5
work horizontally s=ut 10=u*0.5 u=20
31. R=pl/A and A=kd^2 so double the diameter mean divide resistance by 4. V=IR and V is same for wires in parallel so current in P is 4x cuurent in Q

Offline astarmathsandphysics

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Re: physics
« Reply #99 on: April 28, 2010, 09:07:19 am »
20. A cos P=pgh
so 2xp(P)+xp(Q)=2xp(Q) so xp(P)=2p(Q) so p(P)1/2p(Q)
18.work dine=increase in potential energy+heat generated
9000*40=20000*12+H
H=120000J A
11.B m(v-u)=m(-v-v)=-2mv
31. C use P=VI
33.R=pl/A double the length means double R and double the diameter means 1/4 R so R is halved overall
V=IR so double V and hal;ve R mean I is 4x bigger
26 !6 I=kA^2

Offline ruby92

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Re: physics
« Reply #100 on: April 29, 2010, 09:27:31 pm »
O/n 2003 paper 2 CIE physics
Q3 (C) part iii 2. how is the torque of this also 45?

Q5 of the same papers part c

m/j 2004 paper 2
1 (b)
« Last Edit: April 29, 2010, 09:32:50 pm by ruby92 »

Offline ruby92

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Re: physics
« Reply #101 on: April 29, 2010, 11:22:47 pm »
Posted by: astarmathsandphysics
can you post question and paper and year in same post
mj 2004 p1 q8 D - as ball speeds up acc falls as air resistance increases]

9. Work vertically s=ut+1/2at^2 u=0 cos he vertically speed is zero
1.25=0+1/2*10*t^2
t=0.5
work horizontally s=ut 10=u*0.5 u=20
31. R=pl/A and A=kd^2 so double the diameter mean divide resistance by 4. V=IR and V is same for wires in parallel so current in P is 4x cuurent in Q

i dont get 31  ??? ???

Offline ruby92

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Re: physics
« Reply #102 on: April 30, 2010, 01:05:45 am »
M/j 2004 paper 2 physics
5 b
3 B ii
1 b

o/n 2004 paper 2
1 b ii

m/j 2005
3 b we dont convert g to kg?

Offline astarmathsandphysics

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Re: physics
« Reply #103 on: April 30, 2010, 08:17:58 am »
3bii)s=1/2at^2 a=s/(1/2t^2)=2*gradient of graph=
on2004p2 %error =2*0.02/0.50*100=8%
mj2005 you should convert to kg it is good practice but units of grams cancels cos factor of 1000 occurs on both sides

Offline ruby92

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Re: physics
« Reply #104 on: April 30, 2010, 05:39:44 pm »
O/n 2005 paper 2
3 c
« Last Edit: April 30, 2010, 05:42:29 pm by ruby92 »