Bio C. 8

Due to immersion in fluid.

Due to motion of fluid.
Types: Drag and Lift

Force that results from motion within a fluid.
Resolved into:
Drag
Lift Force

Drag is ______.
Lift is ______.

• Velocity of object in fluid
• Velocity of fluid itself
• = the difference between the two

• Force that results from motion within a fluid
• Resolved into
Drag Force
Lift Force

• Lift force caused by a spin
• Responsible for curved flights of balls
Topspin - Ball drops
Backspin - Greater height of flight of ball
Sidespin - Ball swerves right or left

Upward force equal in magnitude to t the weight of water displaced by the immersed object.

• Proportional to density of fluid, frontal area of object and square of relative velocity of fluid.
• Relative velocity has greatest influence on drag and lift because these forces are proportional to square of velocity.
• Components:
Drag
Lift

• The resultant of lift and drag forces
• Point of application of this resultant
• If center of pressure is not directed through the center of gravity of the object, a torque will be produced (object will turn/rotate)

______ reduces by streamlining shape of object and keeping surface smooth

______ controlled by shape and orientation of object.