Operational Definitions/Measurement System Analysis. The focus for this month is on operational definitions. Operational definitions are one key to good data collection. They are a necessary, although not sufficient, condition for good data collection. Plus, we will look at how control charts can be used to evaluate the measurement system.
Air resistance induces a drag force on any body that falls through any atmosphere other than a perfect vacuum, and this drag force increases with velocity until it equals the gravitational force, leaving the object to fall at a constant terminal velocity.
A falling human reaches terminal velocity in about 12 seconds, after which his speed will remain constant. He'll fall about 450 meters in those first 12 seconds, and about 58 meters each second after that. There are 1609 meters in a mile. The fall would take just under 20 seconds. Caveats: A skydiver wearing a Wing Suit can create more wind resistance, and fall more slowly.