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

Choose the correct answer: