Question 220: Properties of Matter

Question

Spherical balls of radius $R$ are falling in a viscous fluid of viscosity $\eta $ with a velocity $v.$ The retarding viscous force acting on the spherical ball is

Accepted Answer

From Stoke's law,
viscous force acting on the ball falling into a viscous fluid
$F = 6\pi \eta Rv$
$	herefore$ $F \propto R$ and $F \propto v$
hence $F$ is directly proportional to radius & velocity.

Answer

inversely proportional to both radius $R$ and velocity $v$

Answer

directly proportional to both radius $R$ and velocity $v$

Answer

directly proportional to $R$ but inversely proportional to $v$

Answer

inversely proportional to $R,$ but directly proportional to velocity $v$

Properties of Matter

Spherical balls of radius R are falling in a viscous fluid of viscosity \eta with a velocity v. The retarding viscous force acting on the spherical ball is

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