PHYSICS PPR 1 HELLP PLZ!!!!!!

[jerry]

Someone plz plz explain as quickly as possible,ALL OF THESE!,exam is tomorro:O

JUNE02..Q21

JUN02..Q35

NOV02..Q14

NOV02..Q32

JUN05..Q13

JUN05..Q29

anyone? :roll:

 

[beacon_of_light]

I don have Nov n june 02 paper, if you could post a link to them, I can help u put.

june05/
Q13: taking moments about P,
CWM =ACWM
(20x3)=(5x2) + (10x2)
60= 10 + 20
60-30 = 30Nm

Next question. Use diffraction grating formula twice....... dxsin theta = nx lambda
keeping theta and d constant .....

n1 x lambda 1 = n2 x lambda 2
3 x lambda = 600x2
lambda = 400nm

 

[samy]

nov o2 quest 14..

ok it is supported at the 40 cm mark so v ve to balance it round it...
v ve to balnce both sidex

20 x 60(distance from 40 mark) = 100 x 10(the mass of ruler will be at 50 cox it is uniform)+ 50 x X
1200 = 100+ 50 x X

now luk one is 1200 v have to make the other side 1200 also to make the rule balance so if v multiply 50 with 4 it becumx 200 thus 200 + 1000 it becum 1200 ....
so 4 cm from the 40 mark is 44 !!!

 

[samy]

nov 02 quest 32

wen the pot diff is neg and current is also neg itx resistance is infinite..because v cannot define it

for +1 check the current at this value it is 50mA change it to A..it becums 0.05..applyin v=IR
v get r 20

ans A!!

 

[samy]

june 02 quest 35..

see the voltage drop across each resistor...R1 V drops from +5 to +3 so drop 0f +2
R2..i dropx from +3 to +2 so net is +1
R3 is drop of +2...

the ration is 2 : 1 : 2

check for the same ratio in the ans and it is C ( 4 : 2 : 4) = 2 :1 :2...

 

[samy]

june 02 quest 21..

use v+v= m/p + m/2p

the volume remain same so solve it n u will get (4/3)p

 

[dollykhan]

question 40 june 07
q-31 nov 07
q-24,30,34,37 june 08
q-31,32 nov 08

 

[samy]

ques 40 june 07..
ans is C
because the nuclei with max num neutrons and least num of electrons will b slowest..
itx because if there will b more elec it will b attracted more due to more pot diff......n more neutronx so that it becums heavy

 

[samy]

quest 31 nov 07

use R=p L/A
diameter is given so it will b R = 4l/d^2
as material is same the resistivity will b same so no need to use p...

wire p is twice as long so 2l and twice diameter is 2d
for Rp= 2l x 4/ (2d)^2
for Rq= L x 4/ d^2

Rp/Rq......1/2

 

[samy]

june o8 quest 24...

wen the material is same the young modulus also same...no need for calculation directly ans C because both wirex r ov steel...

ques 30..

the distance covered with u is ucostheta thus final is u/costheta
(i am not sure how to explain dis one) sry..

ques 37..
by usin potentio meter formula
V= (R1/R1+R2) x V find the voltage across v...which is...

V= 50/150 x 6....=2
use v=ir
v = 2
r = 100 x10^-3
.....I is 20!!

 

[samy]

nov 08...
use R= p L/A..replave a with D as above
for P....4xL/ 2^2
for Q.....4xL/ 1^2...

R= V/I....so reciprocal ur ans to get current ratio that will b 4/1

quest 32...
copper wires are all in parallel with eachother...take their resistance that is 1/10 six wires so it becumx 3/5....
the resistance of steel is 100...it is also in parallel...
so 3/5 + 1/100 = 1/R...
R= 1.6!!!!!!

 

[jerry]

june 02 quest 21..

use v+v= m/p + m/2p

the volume remain same so solve it n u will get (4/3)p

i know tht much,but thing is,how did u solve to get 4/3..lyk i got 5/3
how did u do tht?
thnx

 

[jerry]

nov o2 quest 14..

ok it is supported at the 40 cm mark so v ve to balance it round it...
v ve to balnce both sidex

20 x 60(distance from 40 mark) = 100 x 10(the mass of ruler will be at 50 cox it is uniform)+ 50 x X
1200 = 100+ 50 x X

now luk one is 1200 v have to make the other side 1200 also to make the rule balance so if v multiply 50 with 4 it becumx 200 thus 200 + 1000 it becum 1200 ....
so 4 cm from the 40 mark is 44 !!!

Ummm...wait! :shock:
im still..totally CONFUSED! :? :? :?
i just still dont understand,why did u multiply 50 wid 1200,where did u get 1200 frm?
and how cum this all lead to final answer?
sorry fr nt getting bt cud u plz make it more clearer??
thnks!

 

[samy]

2v= 2m+m/2p

2p= 3m/2v
2x2/3 p = m/v...
4/3 p = m/v..
hence m/v is density so itx the ratio

 

[samy]

nov o2 quest 14..

ok it is supported at the 40 cm mark so v ve to balance it round it...
v ve to balnce both sidex

20 x 60(distance from 40 mark) = 100 x 10(the mass of ruler will be at 50 cox it is uniform)+ 50 x X
1200 = 100+ 50 x X

now luk one is 1200 v have to make the other side 1200 also to make the rule balance so if v multiply 50 with 4 it becumx 200 thus 200 + 1000 it becum 1200 ....
so 4 cm from the 40 mark is 44 !!!

Ummm...wait! :shock:
im still..totally CONFUSED! :? :? :?
i just still dont understand,why did u multiply 50 wid 1200,where did u get 1200 frm?
and how cum this all lead to final answer?
sorry fr nt getting bt cud u plz make it more clearer??
thnks!

ok luk...ruler k aik side pe 20 g balance hai sae...us 20 g ka moment 20 x 60 = 1200 bunta hai sae.... yeh ho gaya aik side ka balance....
phr its sayin k it is uniform meter rule so itx weight must b at 50 position which is the center...weight is 100 and itx distance from pivot is 10 cm so itx moment is 1000 rite...

now put dese both moments equal cox v ve to balane the ruler the moments should b equal for it...

1200 = 1000...

it meanx itx not balance ...dere is less of 200 N on rite side...
dey ve given us 50g mass....so v ve to find the distnce ..k kitnay distance per v will put 50 g ka mass that will make it balance....
200 is wat v need to balance...
so if v multiply 50 with 4 v get 200....it meanx ager hum pivot sey 4 cm k distance pe lagayen gey it will b balance ..dat is 40 + 4 =44 cm...

now get it??? ..
v cant use 36 because v r balancing it from itx weight side..!!

 

[jerry]

2v= 2m+m/2p

2p= 3m/2v
2x2/3 p = m/v...
4/3 p = m/v..
hence m/v is density so itx the ratio

oh okayy..thnks..BUT u just say its 2m +m/2p.???

ddnt u say b4 tht the equation was v+v=m/p+m/2p
so solving this wud give 2v=2m/3p instead of 3m/2p ryt?
ye aik extra m kahan se agyaaa??? :roll: :shock:

 

[samy]

aray bae i simply made deir same denominator..
is terhan hai na...m/p dis is one...n second is m/2p...
i made denominator 2p...how can it b 3p?

(2m +m) / 2p

 

[jerry]

nov o2 quest 14..

ok it is supported at the 40 cm mark so v ve to balance it round it...
v ve to balnce both sidex

20 x 60(distance from 40 mark) = 100 x 10(the mass of ruler will be at 50 cox it is uniform)+ 50 x X
1200 = 100+ 50 x X

now luk one is 1200 v have to make the other side 1200 also to make the rule balance so if v multiply 50 with 4 it becumx 200 thus 200 + 1000 it becum 1200 ....
so 4 cm from the 40 mark is 44 !!!

Ummm...wait! :shock:
im still..totally CONFUSED! :? :? :?
i just still dont understand,why did u multiply 50 wid 1200,where did u get 1200 frm?
and how cum this all lead to final answer?
sorry fr nt getting bt cud u plz make it more clearer??
thnks!

ok luk...ruler k aik side pe 20 g balance hai sae...us 20 g ka moment 20 x 60 = 1200 bunta hai sae.... yeh ho gaya aik side ka balance....
phr its sayin k it is uniform meter rule so itx weight must b at 50 position which is the center...weight is 100 and itx distance from pivot is 10 cm so itx moment is 1000 rite...

now put dese both moments equal cox v ve to balane the ruler the moments should b equal for it...

1200 = 1000...

it meanx itx not balance ...dere is less of 200 N on rite side...
dey ve given us 50g mass....so v ve to find the distnce ..k kitnay distance per v will put 50 g ka mass that will make it balance....
200 is wat v need to balance...
so if v multiply 50 with 4 v get 200....it meanx ager hum pivot sey 4 cm k distance pe lagayen gey it will b balance ..dat is 40 + 4 =44 cm...

now get it??? ..
v cant use 36 because v r balancing it from itx weight side..!!

thank you sooo much!
haha got it now!

 

[jerry]

aray bae i simply made deir same denominator..
is terhan hai na...m/p dis is one...n second is m/2p...
i made denominator 2p...how can it b 3p?

(2m +m) / 2p

Ohhh..ya rite!
math error! :|

 

[samy]

np!...