Question

Two hail stones with radii in the ratio of 1:2 fall from a great height through the atmosphere. Then their terminal velocities are in the ratio of:

• A. $1:2$
• B. $2:1$
• C. $1:4$
• D. $4:1$

Answer 1

Answer: (C)

$1:4$

Terminal Velocity is given by:

$v=\frac{2r^2(\rho -{\rho }_o)g}{9\eta }$

So, $v\propto r^2$

Ratio of their terminal velocity of given two hail stones = $\frac{r^2}{(2r{)}^2}$= $1:4$