Question

The viscous force acting on a rain drop of
radius 0.35 mm falling through air with a
velocity of 1 m/s, is (η = 2 x 10^-6 Ns/m?):​

Answer 1

Here, r=0.3mm=0.03cm,

v=1ms

−1

=100cms

−1

,

η=18×10

−5

poise.

According to stokes law, force of viscosity on rain drop is

F=6πηrv

=6×3.142×18×10

−5

×0.03×100 dyne

=1.018×10

−3

dyne.