# Post Your AS LEVEL PHYSICS PAPER 2 DOUBTS

#### applepie1996

post your doubts and i'll try and clear them

#### raamish

s09 qs 1 need help in calculation of the uncertainty?

#### applepie1996

s09 qs 1 need help in calculation of the uncertainty?
ok i'll check it out now and tell u in a jiffy

ty

#### applepie1996

s09 qs 1 need help in calculation of the uncertainty?
d=m/v
d=m/length^3
d=580/6.0^3
d=2.69 g cm^-3

for uncertainty:
d=m/length^3
δ d/d = δ m/m + 3 δ l/l
= 10/580 + 3 × 0.1/6.0
= 0.0172 + 0.05
δ d/d = 0.0672
δ d = 0.0672 × 2.69
= 0.181
so your answer will be 2.69 + or - 0.18 g cm^-3
I HOPE U GET IT!!!
AND IF U HAV ANY ODER PROBLEMS U R FREE 2 ASK

#### Yousuf Ykr

Can you help me with these past papers doubts

M/J 02- 7b
O/N 02- 9b, 2c
O/N 03- 3 c
M/J 04- 1b
O/N 04- 1b (ii)
M/J 05- 5c, 6b(iii)
O/N 05- 3c

#### applepie1996

Can you help me with these past papers doubts

M/J 02- 7b
O/N 02- 9b, 2c
O/N 03- 3 c
M/J 04- 1b
O/N 04- 1b (ii)
M/J 05- 5c, 6b(iii)
O/N 05- 3c
yup except the 2002 papers i'll check out the others cuz i dun't hav 20002

#### applepie1996

Can you help me with these past papers doubts

M/J 02- 7b
O/N 02- 9b, 2c
O/N 03- 3 c
M/J 04- 1b
O/N 04- 1b (ii)
M/J 05- 5c, 6b(iii)
O/N 05- 3c
oct/nov 2003
c)i)in string S2 force moves to the left ans in string S1 force moves to the right (i can't help u here u hav to imagine it)
ii)1)the centre is the pivot so you have to find moment from the pivot =F x s = 150 x 0.3=45Nm
ii)2)the torque is one of the two forces on the parallel sides which is 150 x 0.3 the distance =45Nm
ii)3)45=F x 0.12 , F=375N

#### raamish

d=m/v
d=m/length^3
d=580/6.0^3
d=2.69 g cm^-3

for uncertainty:
d=m/length^3
δ d/d = δ m/m + 3 δ l/l
= 10/580 + 3 × 0.1/6.0
= 0.0172 + 0.05
δ d/d = 0.0672
δ d = 0.0672 × 2.69
= 0.181
so your answer will be 2.69 + or - 0.18 g cm^-3
I HOPE U GET IT!!!
AND IF U HAV ANY ODER PROBLEMS U R FREE 2 ASK
i had done all the steps i just dont know why u calculated this : δ d = 0.0672 × 2.69

#### Mattman

How do we know how many nodes are there in a tube?

mj 06 question 6

#### applepie1996

Can you help me with these past papers doubts

M/J 02- 7b
O/N 02- 9b, 2c
O/N 03- 3 c
M/J 04- 1b
O/N 04- 1b (ii)
M/J 05- 5c, 6b(iii)
O/N 05- 3c
i didn't get MJ 04 EITHER

#### applepie1996

i had done all the steps i just dont know why u calculated this : δ d = 0.0672 × 2.69
when u add 0.0172 and 0.05 u get 0.067 which is not the uncertainty it is wat u actually get after calculating the uncertainty of the density which is 0.18/2.69=0.067 so lets take 0.18 as w so w=2.69 x 0.0067=0.18

#### raamish

when u add 0.0172 and 0.05 u get 0.067 which is not the uncertainty it is wat u actually get after calculating the uncertainty of the density which is 0.18/2.69=0.067 so lets take 0.18 as w so w=2.69 x 0.0067=0.18
yeh i get dat.. But when we used the formula δ d/d = δ m/m + 3 δ l/l didnt we take the uncertainty out of density. Or did we not?

#### applepie1996

yeh i get dat.. But when we used the formula δ d/d = δ m/m + 3 δ l/l didnt we take the uncertainty out of density. Or did we not?
to get the total uncertainty of the whole not only density

#### applepie1996

Can you help me with these past papers doubts

M/J 02- 7b
O/N 02- 9b, 2c
O/N 03- 3 c
M/J 04- 1b
O/N 04- 1b (ii)
M/J 05- 5c, 6b(iii)
O/N 05- 3c
for oct/04
you just add 4+4 percentage uncertainty of diameter cuz u square the diameter in finding the area

#### Oliveme

post your and i'll try and clear them
Can someone please help me with this question. It's a very small question. Question 5c(i) they haven't told us the directions?
http://www.xtremepapers.com/papers/...nd AS Level/Physics (9702)/9702_s10_qp_21.pdf
http://www.xtremepapers.com/papers/...nd AS Level/Physics (9702)/9702_s10_ms_21.pdf

Thank you very much!
and

http://www.xtremepapers.com/papers/...nd AS Level/Physics (9702)/9702_s10_qp_23.pdf

#### applepie1996

Can you help me with these past papers doubts

M/J 02- 7b
O/N 02- 9b, 2c
O/N 03- 3 c
M/J 04- 1b
O/N 04- 1b (ii)
M/J 05- 5c, 6b(iii)
O/N 05- 3c
M/J 05- 5c, 6b(iii)
5c)as the lines spread they keep going far apart and the farther apart they go the less bright they become
6b(iii)couple is force x distance so now the force is at an angle of 35 so we resolve it so it will be 2.4x10^-12 * sin35 * 2.5x10^-3

#### applepie1996

How do we know how many nodes are there in a tube?

mj 06 question 6
in fig 6.1 there is 1 node and that is where sound is heard and in fig 6.2 sound is heard at the other node which is 32.4cm away

#### applepie1996

Can someone please help me with this question. It's a very small question. Question 5c(i) they haven't told us the directions?
http://www.xtremepapers.com/papers/...nd AS Level/Physics (9702)/9702_s10_qp_21.pdf
http://www.xtremepapers.com/papers/...nd AS Level/Physics (9702)/9702_s10_ms_21.pdf

Thank you very much!
and

http://www.xtremepapers.com/papers/...nd AS Level/Physics (9702)/9702_s10_qp_23.pdf
the left circle will have the positive sign and the right circle will have the negative sign as it always moves from higher potential to lower potential

#### applepie1996

Can you help me with these past papers doubts

M/J 02- 7b
O/N 02- 9b, 2c
O/N 03- 3 c
M/J 04- 1b
O/N 04- 1b (ii)
M/J 05- 5c, 6b(iii)
O/N 05- 3c
I HOPE U GOT WAT I TOLD U!!!