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Cool goIITian

Joined: 14 Mar 2008
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28 Mar 2008 12:37:48 IST
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friction... a B.MAT question....proper solution required.......
None

two blocks of masses ma=2kg and mb=4kg are kept on an inclined plane of inclination  = 37degree as shown.The coefficient of friction bw A and B is 1 and bw B and surface is 2. accelerations of blocks A and B are a1 and a2. then match the following.             column I                                                       &nb


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BALGANESH's Avatar

Blazing goIITian

Joined: 21 Dec 2007
Posts: 1025
28 Mar 2008 13:36:00 IST
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since they have common acceleration
they can be considered as a system
now for the system of A&B
mgsin37 - 2 mgcos37 = ma
gsin37 - 2 gcos37 = a
simplifying we get
6 - 82 = a ---------------------(1)

now for block A
mgsin37 + 1 mgcos37 - ma (pseudo force)= 0
gsin37 + 1 gcos37 = a
simplifying we get
a = 6 + 81 --------------------------(2)
from 1 and 2
6+81 = 6 - 82
or 1 = -2

therefore it is option B

correct me if i"m wrong

BALGANESH's Avatar

Blazing goIITian

Joined: 21 Dec 2007
Posts: 1025
28 Mar 2008 15:22:23 IST
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i think 3 is A and C

1 mgs = 0             1 =0
case 2
2 mgs = 0                2 =0

therefore it is A and C
anchit saini's Avatar

Blazing goIITian

Joined: 1 Feb 2008
Posts: 1251
28 Mar 2008 15:36:01 IST
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what i think is that since u have said a1 = a2 only when option B is correct
hence
a1 ! = a2 when option a,c,d are correct

Cool goIITian

Joined: 14 Mar 2008
Posts: 36
29 Mar 2008 21:20:44 IST
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hey the answrs according to the solution given by Brilliant tutorials is:
 
1. A,B
2. C,D
3. A,B,D
4. A,C
 
and my friend ganesha..u can consider it as a system only wen u can confirm that they move together..please justify...
i am really very tensed about such kind of questions..pls somebody help........with proper solution..

New kid on the Block

Joined: 31 Mar 2008
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Hot goIITian

Joined: 7 Aug 2007
Posts: 184
31 Mar 2008 22:15:26 IST
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THE FIRST PART..

Hot goIITian

Joined: 7 Aug 2007
Posts: 184
31 Mar 2008 22:16:32 IST
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SECOND AND THIRD PART..

Hot goIITian

Joined: 7 Aug 2007
Posts: 184
31 Mar 2008 22:17:31 IST
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FOURTH PART..
BALGANESH's Avatar

Blazing goIITian

Joined: 21 Dec 2007
Posts: 1025
31 Mar 2008 22:18:10 IST
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ok for the first one A is correect
as there is no friction between the wedge and block B the whole A and B can be considered as one system with common acceleration

so from my present and previous post
the answer for 1 is
A) and B)
BALGANESH's Avatar

Blazing goIITian

Joined: 21 Dec 2007
Posts: 1025
31 Mar 2008 22:20:14 IST
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since a1 is not equal to a2 the other two options must be true fior this
therefore for 2 answer is
C) , D)

[ thanks anchit]

New kid on the Block

Joined: 31 Mar 2008
Posts: 9



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