EXAMPLE 1:
Your high school physics teacher decides to quit his job and become a daredevil. In his newfound need for speed, he gives sky-diving a try.
Once jumping from the plane, he spreads out and assumes the flat, square position shown in the picture (Cd = 1.28). Make your own estimations for area.
Assuming he weighs 70 kg, what will be his maximum speed (otherwise known as his terminal velocity)?
EXAMPLE 2:
Sadly, this fast speed was not enough for this adrenaline junkie. He readjusts midair to dive head first which changes his shape from a square to a cylinder (Cd = 0.82).
This changes both the impact area as well as the drag coefficient. Make your own estimations for radius and length of the body.
What is his new terminal velocity?
Photo credits:
Spread skydiver: http://www.landairsea.com/gps-tracking-blog/skydiver%E2%80%99s-experience-exemplifies-durability-of-gps-infrastructure/
Head-first skydiver: http://www.corporate-eye.com/blog/2010/09/employer-branding-us-army/