Mechanics - friction problem

62

Lokesh Verma ·2008-12-30 06:33:41

See if this fbd helps!

the small block m is moving with the same horizontal velocity as the larger mass M
And M has no vertical velocity. While m has. This clearly says that the relative motino is along surface...

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11

Subash ·2008-12-30 04:43:58

@priyam ans is wrong now what

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skygirl ·2008-12-30 04:49:09

yup same equations ...

i mean force equations...

and am very sorry about the constraint eqn...

it will be -a1+2a2 = 0 ..

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11

Subash ·2008-12-30 04:57:51

but still i am not getting the answer

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skygirl ·2008-12-30 05:00:33

is it?
okie lemme try.........

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skygirl ·2008-12-30 05:05:51

i think there sumthnng wrong.....

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62

Lokesh Verma ·2008-12-30 06:19:25

sankara!!! NO!! :O

It oppsosed relative motion of the surface of contacts!!!!

How did u manage to find the relative motion of the surfaces in that direction! :O

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3

msp ·2008-12-30 06:25:20

sir doesnt the contact surface of M is moving horizontally

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62

Lokesh Verma ·2008-12-30 06:25:55

it does.. but then is the relative motion between M and m in the direction u have shown!?

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3

msp ·2008-12-30 06:31:04

sir can u please give me the vector formof the frictional force

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33

Abhishek Priyam ·2008-12-30 04:35:03

Made some edits above in second equation

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Subash ·2008-12-30 08:38:55

Is the tensional force due to the upper pulley on the massM acting both downwards and sideways

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62

Lokesh Verma ·2008-12-30 08:42:01

yup..

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11

Subash ·2008-12-30 10:23:33

These are my equations

R=T+Mg+f1
2T-N-n2(T+f1+Mg)=2Ma

mg-T-n1N=ma
N=2ma

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11

Subash ·2008-12-30 10:27:25

Are these equations rite . i dont feel so because i hav taken static friction for both i am not sure but i could not write any other eqn

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33

Abhishek Priyam ·2008-12-30 19:00:34

Lol...

i am a fool my eqn were 105% wrong :(

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62

Lokesh Verma ·2008-12-30 20:45:35

subash have u taken the wrong values of a and 2a..

I think that the vertical acceleration will be 2a .. while the horizontal will be a each :)

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11

Subash ·2008-12-31 04:39:21

identified my mistake thnx bhaiyya

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1

kIrTi kUmAr kAsAt ·2008-12-31 04:50:08

http://www.physicsfundas.com/hcvermasolutions/06.SOLUTIONS%20TO%20CONCEPTS.pdf

find the full solution to ur problem here!!!!

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11

Subash ·2008-12-30 00:52:33

@ sky girl Doesnt the frictional force between the blocks act on M too?
why dint you take it into account

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Subash ·2008-12-29 21:57:03

Find the acceleration of mass M in the situation. The coefficient of friction between the blocks is n1 and that between the bigger block and the ground is n2