Physics and Math Chapter 4: Fluids Flashcards
What are fluids?
Substances that have the ability to flow and conform to the shape of their containers.
What forces can fluids exert/notwithstand?
Can exert perpendicular, cannot withstand shear force.
Which phases are considered fluid?
liquids and gases
What is density?
Mass per unit volume of a substance
What is pressure?
measure of force per unit area; it is exerted by a fluid on the walls of its container and on objects placed in the fluid
Is pressure a scalar or vector quantity?
scalar - no direction; the pressure exerted by gas on the walls of its container will always be perpendicular to the container walls.
What is absolute pressure?
Sum of all pressures at a certain point within a fluid. It is equal to the pressure at the surface of the fluid, usually atmospheric pressure, plus the pressure due to the fluid itself.
What is gauge pressure?
name for the difference between absolute pressure and atmospheric pressure. In liquids, gauge pressure is caused by the weight of the liquid above the point of measurement.
What is Pascal’s principle?
states that an applied pressure to an incompressible fluid will be distributed undiminished throughout the entire volume of the fluid.
What are hydraulic machines?
operate based on the application of Pascal’s principle to generate mechanical advantage.
What is archimede’s principle?
Governs bouyant force. When an object is placed in a fluid, the fluid generates a buoyant force against the object that is equal to the weight of the fluid displaced by the object.
What determines if an object will float or sink?
If the maximum bouyant force is larger than the force of gravity, then it will float (if object is less dense than the fluid it is in). If the maximum buoyant force is smaller than the force of gravity on the object, then the object will sink (if the object is more dense than the fluid it is in.)
Which way does the buoyant force face?
Opposite of gravity
What is viscosity?
measurement of a fluid’s internal friction.
What is viscous drag?
nonconservative force generated by viscosity.
What is laminar flow?
Smooth and orderly, rate is determined by Poiseuille’s law.
What is turbulent flow?
Rough and disorderly, causes the formation of eddies.
What is the continuity equation?
statement of the conservation of mass as applied to fluid dynamics
What is Bernoulli’s equation?
expression of conservation of energy for a flowing fluid. States that the sum of the static pressure and the dynamic pressure will be constant between any two points in a closed system.
What is static pressure?
Associated with the height of liquid
What is dynamic pressure?
Associated with the movement of liquid.
What is the Venturi effect?
For horizontal flow, there is an inverse relationship between pressure and speed and in a closed system, there is a direct relationship between cross-sectional area and pressure exerted on the walls of the tube.
What is adhesion?
the attractive force that a molecule of the liquid feels toward the molecules of some other substance.
What is cohesion?
the attractive force that a molecule of the liquid feels toward other molecules of the same liquid
What does the circulatory system behave as?
A closed system with non-constant flow
What is arterial circulation motivated by?
the heart
What is venous circulation motivated by?
skeletal musculature and expansion of the heart
What does inspiration and expiration create?
a pressure gradient for the respiratory and circulatory system.
What does flow rate depend on?
radius of the tube, pressure gradient, viscosity and length of the tube.
