IIT JEE , AIEEE Forum - Physics , Mechanics

cyborg

Sure for Aieee ....................................................A liqd is rotating abt its axis @ 4

rad/s in a vessel of radius 0.05m. Can you find the rise in level of the liqd?

a) 0.05m

b)0.03m

c)0.02m

d)0.01m

Support wid soln

ziauddin75

how can you be so sure

cyborg

if u get this right u can be sure of getting atleast one type aieee qstn right

anchitsaini

should be 2 cm

cyborg

can u give the soln. I have a feeling u're right .

anchitsaini

well i think what is being asked here is the rise in level of ends with respect to the centre--

let us consider a pt having coordinates(x,y)
the forces acting on it are
mxw^2
mg

tan theta=mxw^2/mg
also tan theta=dy/dx
therefore
dy/dx=w^2x/g
on integrating
y=w^2*x^2/2g

at the ends
x=radius=0.05m
therefore--
y=(16pie^2*25*10^-4) /2*10
=0.02m

anchitsaini

here is the image

sidsgr88

The ans is c 2cm
From bernoullis theo..
We have p*v2/2=p*g*h
Since we were comparing the points in the tube just bfore and at the end so h=0 n v=0 resp..
For v=wr
Substitute the values and ans is 2cm

cyborg

I solved by ur way sid . Anchit went a little too deep into the problem

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