1. Fluid Properties
Chapter 16 Section 2

2. What is a Fluid? Fluid: any matter that can flow
Flow: movement of the matter
The matter does not have a definite shape

3. Density Density is the mass in a given volume As an equation:
ρ = m/V
In fluids, less dense materials will float on more dense materials

4. Viscosity Viscosity: Resistance to flow
High viscosity fluid does not want to flow much
Due to the chemical nature of the fluid
Temperature affects viscosity… how?

5. Buoyancy and Archimedes
Pressure in fluids:
Force exerted over a given area
P = F/A
The force acts on all surfaces
The force is perpendicular to the surface
In a fluid, pressure increases with depth
The force is the weight of the fluid

6. Buoyancy and Archimedes
Buoyancy: The upward force a fluid puts on an object in the fluid
If the buoyant force equals or is greater than the object’s weight, the object floats

7. Buoyancy and Archimedes
Archimedes discovered:
An object placed into a fluid displaces the fluid
If the weight of the displaced fluid is greater or equal to the weight of the object, the object floats
If the weight of the displaced fluid is less than the weight of the object, the object sinks
Density determines the weight of the fluid and the object!

8. Pascal’s Principle If a fluid is in a confined container:
External pressure applied at one location is transmitted equally throughout the fluid
We use this in:
Hydraulics!

9. Math Skills Activity p 499
A hydraulic lift is used to lift a heavy machine that is pushing down on a 2.8 m2 piston with a force of 3700 N. What force needs to be applied to the m2 piston to lift the machine?
What we know:
F1 = 3700 N A1 = 2.8 m2
F2 = ? A2 = m2

10. Math Skills Activity p 499 Continued
What equation?
P1 = P2
Remember, P = F/A
So F1/A1 = F2/A2
And F2 = (F1)(A2) A1
Put the numbers in!
F2 = (3700 N)(0.072 m2)
2.8 m2

11. Math Skills Activity p 499 Continued
Solve!
F2 = (3700 N)(0.072 m2) = N
2.8 m2
Check number and units!

12. Bernoulli’s Principle
As the speed of fluid flow increases, the pressure exerted by the fluid decreases
We use this:

13. YouTube - Julius Sumner Miller - Physics - Bernoulli pt. 1