Exam 2 Flashcards
(53 cards)
Buoyant Force
a reaction to the pressure the fluid exerts on the object
Pressure on a submerged object is the same from all directions if you stay at the
same depth
Buoyant force increases with
increasing size of object and increasing pressure
Pressure increases the deeper you go due to the
increasing weight force of fluid above the object
Buoyancy
the force that acts on an object in fluid
Buoyancy is
always vertical, caused by pressure, and influenced by size
Archimedes’ Principle
the buoyant force is equal to the weight of the volume of fluid displaced by the object
Fb < W
sinks
Fb > W
rises
Fb = W
floats
Specific gravity
the ratio of the weight of the object to the weight of an equivalent volume of water
Specific Gravity less then or equal to 1
floats
Specific gravity greater then or equal to 1
sinks
Density
ratio of mass to volume
Density of water
1000 kg/m3
Density of air
1.2kg/m3
Center of Volume
the point around which a body’s volume is equally distributed and at which a buoyant force acts
Dynamic Fluid Force
includes the lift and drag force that act on an object
Relative Velocity
the difference between an object’s velocity and the surrounding fluid’s velocity
Drag Force
one component of dynamic fluid force, and it is the component that slows down the object as it moves through the fluid
Two types of drag force
surface drag and form drag
Surface Drag
caused by friction between the fluid and the surface of the object
at slower velocities
Form Drag
caused by sum of the impact forces of the fluid molecules with the object
at faster velocities
Lift Force
acts on the object in a direction perpendicular to fluid flow & changes the direction of the object’s motion
