Bob Swinney wrote:

Spehro Sez: "Acceleration depends on the force and the mass (a = f/m). The
net force is the force from gravity minus the drag from the air. Obviously
at the terminal velocity the acceleration is zero."

A fine point for sure! But acceleration is, as you said = force/mass. Not
sure if you meant to say that air drag has an influence on acceleration from
the force of gravity. I don't think it does. Air drag will effect the
resulting velocity, but acceleration from gravity is a constant.

An object, for simplicity, falling straight down in still air has two
forces acting on it, the force of gravity, m/g, and the force of
aerodynamic friction. These will act in opposite directions and will be
equal at terminal velocity.

Ignoring this will just confuse you.

Ted