Properties of Fluids

16-2

Buoyancy

• Ability of liquid or gas to exert an upward force on an object immersed in it

• If the buoyant force is equal or greater than the object’s weight, the object will float

Archimedes’ Principle

• The buoyant force on an object is equal to the weight of the fluid displaced by the object

• Density = mass per unit of volume; higher density objects may not displace enough water to float!

Pascal’s Principle

• Pressure is the force exerted per unit area; air and water both press on us

• Pressure applied to a fluid is transmitted throughout it

• Pressure applied to a small surface is magnified at a larger surface

Bernoulli’s Principle

• As the velocity of a fluid increases, the pressure exerted by that fluid decreases

• Airplanes !!!!!!

Viscosity

• Fluids tend to flow

• The resistance to flow is viscosity; “thicker” fluids have a higher viscosity and tend to flow slower