FLUIDS

STATICS

I. A fluid is a substance that can flow.

II. Density is the mass per unit volume.

A. Weight density

B. Mass density

III. The pressure is the ratio of the normal force dF exerted on the area dA to the size of dA: p = dF/dA

IV. How does the pressure vary with the distance below the surface of a fluid?

C. Notes:

1. The pressure doesn't depend on the shape of the container.

2. The pressure is the same at all points at the same depth in all directions.

D. A fluid transmits an applied pressure. What does F = (A/a)f mean?

E. What is Archimedes' Principle?

DYNAMICS

I. We assume that when a fluid flows it is steady, irrotational, incompressible, non-viscous, and that we can use streamlines. Streamlines are parallel to the velocity of the fluid at every point.

II. What is the Equation of Continuity and what are the restrictions on it?

III. What is Bernoulli's Equation?

EXAMPLE

A large tank of water has a small hole near the bottom, a distance h below the surface. What is the speed of the water coming out of the hole?