• Question: why does rain not gain velocity as it falls and therefore be hitting the ground at very high speeds?

    Asked by willydowner to Arttu, Ceri, James_M on 23 Jun 2011.
    • Photo: Ceri Brenner

      Ceri Brenner answered on 23 Jun 2011:

      there’s something called the terminal velocity, it’s the velocity at which the air resistance equals the gravitational force on the droplet and so the droplet no longer accelerates because there is no overall force acting on the object and so it remains at a fixed velocity (newton’s first law). The terminal velocity of a falling object depends on it’s shape, and apparently the terminal velocity for an average raindrop is about 10 m/s