Chapter 6 Quiz Flashcards
(19 cards)
how do water and air act?
like fluids
what forces do air and water exert?
hydrostatic pressure, buoyancy, drag, and lift.
hydrostatic pressure
the force exerted by a fluid (air or water) to support its own weight.
atmospheric pressure
gravitational pull keeping us on the ground. greatest at sea level. 14.7 PSI = 1 atmosphere.
water
more than 800 times denser than air. every 33 feet down in water increases pressure by 1 atmosphere.
buoyancy
the tendency of an object to float or rise when submerged in a fluid. one of the few forces that lift upward and fight gravity.
archimedes principle
the buoyant force acting on an object is equal to the weight of the fluid that the object displaces.
center of buoyancy
the place where the buoyant force concentrates its upward push.
floating position
normally buoyant force just below ribcage.
drag
a collection of fluid forces that oppose the actions an athlete is trying to perform.
relative motion
motion of one object relative to the other.
weather conditions
air temperature, barometric, humidity.
fluid viscosity
stickiness of fluid. resistance to flow.
surface drag
also called viscous or skin friction. athletes move through air or water.
form drag (shape, profile, or pressure drag)
produced by the shape and size of the athlete.
circular drag
circular objects cause more drag because you cant redesign them like other objects.
wave drag
drag created by the action of the waves at the interface where water and air meet.
lift
discus applies force to the air, and the air reacts by applying force to the discuss.
magnus effect
spin of the ball influences flight. backspin means it hangs in the air, and topspin means it flies forward and down.
