Exam Study Notes

Viscosity is a liquid's thickness or resistance to flow.
Flow rate measures a liquid's viscosity, typically in ml/s (milliliters per second).
Flow rate allows comparison of different fluids' viscosity.
Thicker fluids flow slower and are more viscous.
Viscosity is important in industries like the car industry (motor oils) and the food industry (sauces).

Temperature affects viscosity.
- Increasing temperature lowers viscosity.
- Lowering temperature increases viscosity.
Practical application: Use ice to lower the temperature of bubble gum to make it more viscous and easier to remove.

Density is an object's mass divided by its volume.
Formula: $D = \frac{m}{v}$
Units differentiate solid and liquid density calculations.
- Solids: $d = \frac{grams}{cubic \, centimeters}$
- Liquids: $d = \frac{grams}{milliliters}$
Volume determination for irregular shapes: Submerge the object in a full water container; the displaced water's volume equals the object's volume.

A memory method helps solve density problems.
Arrange M (mass), d (density), and V (volume) in a triangle with M on top and dV on the bottom.
Cover the variable to be calculated to reveal the necessary operation (multiplication or division).
- Covering M leaves dV, indicating density × volume = mass.

Density depends on the weight of atoms and molecules and the space between them.
Density is affected by whether the object is solid or contains air pockets.
Temperature changes impact density.
A hydrometer uses buoyancy to measure density.
Density relies on the concentration of a solution (solute in solvent); higher concentration yields greater density (e.g., saltwater vs. freshwater).
Ships float due to their large air volume, making overall density less than water density.

An object submerged in fluid experiences a buoyant force equal to the weight of the displaced fluid.
The buoyant force equals the weight of the displaced fluid.

Pressure is the force experienced by an object divided by the surface area on which the force acts.
$P = \frac{F}{A}$
The unit for pressure is the pascal (Pa) or N/m\textsuperscript{2}.
Atmospheric pressure is exerted by the weight of the air above us.

Compressibility is the ability to decrease volume when pressure is applied.
Gases are highly compressible; increased pressure decreases volume.
Liquids are nearly incompressible; pressure increase does not change volume significantly.
Liquid particles are already close together, pressure is exerted everywhere on the container's inner surface (fluid pressure).

Pressure applied to an enclosed fluid is transmitted undiminished to every part of the fluid and the container walls.
Pascal's principle explains hydraulic systems, such as a lift for raising cars.

Hydraulic systems operate via liquid movement or force exerted by a liquid within a closed system.

Pneumatic systems operate via gas movement or force exerted by a gas within a closed system.
The gas must be compressed before applying pressure.
Force is applied throughout the fluid.