Author Topic: P1 CIE physics doubts  (Read 7778 times)

Offline sweetie

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P1 CIE physics doubts
« on: April 25, 2010, 07:33:38 pm »
Q10, 11 and 32

thanx 4 any help!!!!

~ A.F ~

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Re: P1 CIE physics doubts
« Reply #1 on: April 25, 2010, 07:34:34 pm »
I'm on it :)

~ A.F ~

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Re: P1 CIE physics doubts
« Reply #2 on: April 25, 2010, 07:44:02 pm »
Q10, 11 and 32

thanx 4 any help!!!!

PS; I haven't got the answers..soc heck'em pls :) :

Q.10: v1-v2/u2+u1=1

therefore u1+u2=v2-v1------> D

Q.11:

You must write down the equations for both objects:

1) box-----> T-6= 2a----> T=28+6
2) 2 KG---> 2g-T=2a----> T=2g-2a

now we got 2 Ts equations:

8a+6=2g-2a

10a= 2g-6

a= 1.4---->A

Hope you got that :D

nid404

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Re: P1 CIE physics doubts
« Reply #3 on: April 25, 2010, 08:04:15 pm »
thanks + rep  ;D

it goes up by 2 :D

~ A.F ~

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Re: P1 CIE physics doubts
« Reply #4 on: April 25, 2010, 08:08:57 pm »
Thank you Nid  ;D  :-*

Offline sweetie

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Re: P1 CIE physics doubts
« Reply #5 on: April 25, 2010, 08:46:37 pm »
PS; I haven't got the answers..soc heck'em pls :) :

Q.10: v1-v2/u2+u1=1

therefore u1+u2=v2-v1------> D

Q.11:

You must write down the equations for both objects:

1) box-----> T-6= 2a----> T=28+6
2) 2 KG---> 2g-T=2a----> T=2g-2a

now we got 2 Ts equations:

8a+6=2g-2a

10a= 2g-6

a= 1.4---->A

Hope you got that :D


for Q10 , arent v1 and v2 moving in same direction , so their signs should be the same , nd the signs of u1 and u2 should be diff.????

~ A.F ~

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Re: P1 CIE physics doubts
« Reply #6 on: April 25, 2010, 08:52:20 pm »
lol no..

there's that thing called coefficient of restitution, e,=

e= v1+- v2/u1+-u2

sign is positive when directions are similar..e=1 when collision is PERFECTLY elastic :)

Offline astarmathsandphysics

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Re: P1 CIE physics doubts
« Reply #7 on: April 25, 2010, 09:12:59 pm »
For restitution
If moving in same direction closing speed or parting speed = bigger speed - smaller spedd
If movin towards each other clsong spped =sum of speeds

Offline astarmathsandphysics

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Re: P1 CIE physics doubts
« Reply #8 on: April 25, 2010, 09:14:59 pm »
And if they are moving apart separation speed = sum of speeds

Offline sweetie

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Re: P1 CIE physics doubts
« Reply #9 on: April 25, 2010, 11:30:21 pm »
ok ppl,
cn sum1 xplain Q32 as well nd Q11 and 10 too  ( am not gettin them :-[)
Thank You

Offline astarmathsandphysics

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Re: P1 CIE physics doubts
« Reply #10 on: April 25, 2010, 11:33:08 pm »
year? I suppose p1

Offline sweetie

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Re: P1 CIE physics doubts
« Reply #11 on: April 25, 2010, 11:41:49 pm »
its nov08 ( i've attached the file) :)

Offline astarmathsandphysics

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Re: P1 CIE physics doubts
« Reply #12 on: April 26, 2010, 12:03:20 am »
10 approach speed=u1+u2
separation speed=v2-v1
they are equal for elastic collisions  D
11.res for both particles using F=ma
for 2g particle 2g-T=2a (1)
for 6g particle T-6=6a (2)
(1) +(2) 2g-6=8a so a/(2*9.8-6)/8=1.7 B
32)1/R=1/100+1/10+1/10+1/10+1/10+1/10+1/10=61/100
R=100/61 B

Offline dodo

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Re: P1 CIE physics doubts
« Reply #13 on: April 26, 2010, 03:58:10 pm »
hi would please help me in answering this question and plesa while answering explain how u progressed to this result
the paper is may/june CIE physics 2009
question 5 part b) :)

nid404

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Re: P1 CIE physics doubts
« Reply #14 on: April 26, 2010, 04:19:47 pm »
hi would please help me in answering this question and plesa while answering explain how u progressed to this result
the paper is may/june CIE physics 2009
question 5 part b) :)

here u go

there is a formula u need to know

phase difference=( 2pi/ lamda)  X path difference

phase difference = pi [ for destructive interference]
lambda(wavelength) = 2pi/ pi  X path difference.
path difference is S2M - S1
find S2M using Pythagoras = root of 802 + 1002
                                                   =128
path difference= 128-100=28
wavelength= 2pi/pi X 28
               =56cm                 
At f= 1KHz wavelength= 0.33m/ 33cm
At f=4kHz   wavelength= 0..0825/8.25cm
wavelength changes from 33cm to 8.25cm
for minima...phase difference should be either one of them pi, 3pi,5pi,7pi [sub them in the eqn]
minima is observed when lambda= 56cm, 18.7cm, 11.2cm, 8cm
which are the 2 values between 33 and 8.25?? 18.7 and 11.2...so only 2 minimas