Question
Physics Question on mechanical properties of fluid
Raindrops falling down attain limited value of velocity because of
A
surface tension effects
B
air currents in atmosphere
C
viscous forces exerted by air
D
upthrust of air
Answer
viscous forces exerted by air
Explanation
Solution
When raindrop moves downward through air, an upward drag (viscous) force acts on it. This force depends on velocity of the raindrop. After certain time, this force becomes equal to the weight of the raindrop and it falls with constant velocity.