If a small raindrop falls through air

When a small raindrop falls through the air, it is initially accelerated by the force of gravity, causing its velocity to increase [t5]. However, as the velocity increases, the aerodynamic drag (air resistance) acting in the opposite direction also increases [t1, t7]. Eventually, the magnitude of this drag force, combined with buoyancy, equals the downward gravitational force [t1, t4]. At this point, the net force on the raindrop becomes zero, and it stops accelerating [t3, t8]. Consequently, the raindrop continues to fall at a constant speed known as terminal velocity [t1, t3]. This physical process ensures that raindrops do not continuously accelerate to dangerous speeds, but instead reach a steady state where the resistance of the air balances the pull of gravity [c1, t4].

Sources

1. [1] https://www.sciencedirect.com/topics/physics-and-astronomy/terminal-velocity
2. [2] https://sathee.iitk.ac.in/article/physics/physics-terminal-velocity/
3. [3] Physical Geography by PMF IAS, Manjunath Thamminidi, PMF IAS (1st ed.) > Chapter 24: Hydrological Cycle (Water Cycle) > Precipitation > p. 337