A small drop of water is released from a cloud with initially zero velocity.
It's subsequent speed is determined by gravity (g=9.81 m/s²)
and air resistance which is proportional to the square of the velocity :
For a spherical rain drop of 6 mm ( about 1/4 inch ) diameter we have :
Force of air resistance = k * v2 with
v = velocity [m/s]
Force of gravity : 1.1*10-3 [N]
- What is the terminal velocity of the rain drop ?
HINT : what happens to acceleration as terminal velocity is approached ?
- Determine the equation for the speed v as function of distance y
(t=0 , y=0 , v=0)
HINT : don't use a=dv/dt
- Based on your equations at which distance has the drop reached 90 % of its terminal velocity ?