To stay suspended at a fixed position, the amount of air resistance rushing the sky divers up must be the same as the amount of gravitational force pulling them down. Observe the positions adopted by the skydivers to control their movements. What positions must they adopt to move upwards and downwards?
The secrets of cycling
Cycling can be a highly competitive sport. Observe the positions of the cyclists, the shape of their helmets and their outfits in their relentless pursuit to reduce frictional force acting on them.