Question

If the radius of a droplet becomes half, what would be its terminal velocity? A=4times..b=One Fourth?which option is correct a or b ?

Answer 1

here you go let me know if you need more help

If a spherical body of radius r and density ρ falling through a viscous medium of density σ and having coefficient of viscosity η

As the body falling through viscous medium, its velocity and viscous forces increases. At a particular point the sum of the viscous and buoyant forces of the body equals to the gravitational force on it. From this point the body enters into adynamic equilibrium state, in this dynamic equilibrium the velocity of the body is called as terminal velocity (Vt).

In the dynamic equilibrium state Fnet = 0

Fv + Fb = Fg………….Eqn(1)

From Eqn(2) We can arrive at

6π ηrVt = 4/3 π r >3 g (ρ–σ)……..Eqn(2)

Vt = 2 r >2 g (ρ–σ/9η ……..Eqn(3)

If radius becomes half then r’ = r/2

New Vt’=?

Vt’/Vt = r’>2/r>2

By plugging in the value of r’ in the above relation.

Vt’/Vt = (r/2)>2/r>2

Vt’/Vt = 1/4

Vt’ = Vt/4

Result : Terminal velocity of the body reduces by 4 times.

Answer 2

yeah dusre questions ka answer h

is ka answer b hoga it means one fourth.