Question

The viscous force acting on a small spherical rain drop falling through stormy air cannot be calculated using Stoke's law because ____________.

Options

• the medium through which the rain drop is falling is not liquid

• the dimensions of rain drop is negligible

• the motion of air layers relative to raindrop is not streamlined

• all of the above

Answer 1

The viscous force acting on a small spherical rain drop falling through stormy air cannot be calculated using Stoke's law because the motion of air layers relative to raindrop is not streamlined.

Explanation:

Only if there is no slip between the body and the layers of fluid in contact, and the fluid layers velocity relative to the body remains streamlined, does Stoke's law apply.