1. Pressure increases with depth:
2. Two points at the same vertical position experience the same pressure, no matter what the shape of the container.

P₂ = P₁ + ρgh

A typical problem involves an object floating, or submerged, in a fluid. First draw the free-body diagram and apply Newton's Second Law. Then bring in the buoyant force:

F_b = ρV_disp g = m_disp g

Any two points in a flowing fluid are related by Bernoulli's equation:

ρgy₁ + ½ρv₁² + P₁ = ρgy₂ + ½ρv₂² +P₂

The trick in applying Bernoulli's equation properly is to throw away some of the terms right away.

Bring in the continuity equation to relate velocities:

A₁v₁ = A₂v₂