Question

At about 55 meters/sec, a falling parachuter (before the parachute opens) no longer accelerates. Air friction opposes acceleration. Although the affect of air friction begins gradually, imagine that the parachuter is free falling until terminal speed ( the constant falling speed) is reached. How long would that take?

Answer 1

The acceleration of gravity on Earth is about 9.8 m/s².
That means that if air resistance is neglected, a falling body
smoothly gains 9.8 m/s of downward speed each second.

If our intrepid chutist lightly stepped out of the plane or was
gently pushed, so that his initial downward speed was zero
and grew by 9.8 m/s every second, then it took him ...

               (55) / (9.8)  =  5.6 seconds

to reach that particular downward speed.