EXAMPLE 1:
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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.
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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.
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Assuming he weighs 70 kg, what will be his maximum speed (otherwise known as his terminal velocity)?
![](https://static.wixstatic.com/media/1c3841_3d6760a3d67e1bd691d07ad2fd79982e.jpg/v1/fill/w_495,h_345,al_c,q_80,usm_0.66_1.00_0.01,enc_auto/1c3841_3d6760a3d67e1bd691d07ad2fd79982e.jpg)
​EXAMPLE 2:
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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.
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What is his new terminal velocity?
![](https://static.wixstatic.com/media/1c3841_ffd20bb168befd45e1000d4b13115b60.jpg/v1/fill/w_435,h_340,al_c,lg_1,q_80,enc_auto/1c3841_ffd20bb168befd45e1000d4b13115b60.jpg)
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/