Stoke's law and its applications

[logearav]

Homework Statement

Stoke's law states that retarding force is proportional to velocity. An example is falling rain drop in air.
My book states that " if a rain drop falls, it accelerates initially due to gravity. As the velocity increases, the retarding force force also increases. Finally, when viscous force plus buoyant force becomes equal to force due to gravity, the net force becomes zero and so does the acceleration.
The rain drop then descends with a constant velocity

Homework Equations

The Attempt at a Solution

My question is, if acceleration is zero, how the rain drop would move with constant velocity?

 

[Dick]

Acceleration is the rate of change of velocity with time. If acceleration is zero, how can the velocity change?

 

[logearav]

So, even if there is no acceleration, a body will move. Am I interpreted right?
Thanks for the reply Mr. Dick

 

[Dick]

So, even if there is no acceleration, a body will move. Am I interpreted right?
Thanks for the reply Mr. Dick

If a body is a rest and there is no acceleration, it will not start moving. If body is moving at velocity v and there is no acceleration then it will continue moving at velocity v.

 

[logearav]

I got it now. Thanks a lot Mr. Dick