Fluid Mechanics
Fluid mechanics studies the behaviour of liquids and gases at rest and in motion, including pressure, flow, buoyancy, and the applications of Bernoulli's principle.
What You Need to Know
Key Concept Diagram
Pressure in a fluid increases with depth: P = P0 + rho x g x h
Archimedes' principle: an object in a fluid experiences a buoyant force equal to the weight of fluid displaced
Bernoulli's principle: faster-moving fluids exert less pressure than slower-moving fluids
The continuity equation: A1 v1 = A2 v2 — fluid flow rate is constant in an enclosed pipe
Viscosity is a fluid's resistance to flow; water has low viscosity, honey has high viscosity
Key Vocabulary
Buoyancy
The upward force exerted on an object by the fluid it displaces
Bernoulli's principle
The principle that fluid pressure decreases as fluid speed increases
Viscosity
A measure of a fluid's resistance to flow
Continuity equation
The principle that fluid flow rate is conserved in a closed system
Knowledge Check
Select the correct answer for each question. Click "Check Answer" to see if you are right.
Question 1
According to Archimedes' principle, an object floats when:
Question 2
Bernoulli's principle explains why aircraft wings generate lift because:
Question 3
In a pipe that narrows, the fluid velocity:
Key Concepts Summary
- ●Pressure in a fluid increases with depth: P = P0 + rho x g x h
- ●Archimedes' principle: an object in a fluid experiences a buoyant force equal to the weight of fluid displaced
- ●Bernoulli's principle: faster-moving fluids exert less pressure than slower-moving fluids
- ●The continuity equation: A1 v1 = A2 v2 — fluid flow rate is constant in an enclosed pipe
- ●Viscosity is a fluid's resistance to flow; water has low viscosity, honey has high viscosity