Fluids and Solids

Question 0

Specific Gravity

Answer 0

The ratio of substance density to that of water.

Question 1

Density

Answer 1

ρ = m/V, in kg/m^3

Density of water is 10^3 kg/m^3 = 1 gm/cm^3

Question 2

Pressure

Answer 2

P = F/A, units = N/m^2 = Pa

1 atm = 1.013 X 10^5 Pa

Question 3

Absolute Pressure

Answer 3

Below the surface of a liquid, the pressure depends in gravity and surface pressure. Pressure depends only on the density of the liquid and it increases with depth linearly.
P = (surface Pressure) + ρg(depth)

Question 4

Gauge Pressure

Answer 4

The difference between atmospheric and absolute pressure.

Question 5

Pascal’s Principle

Answer 5

Pressure applied to an enclosed fluid is passed on equally at all points within that fluid. The change in pressure is equal between both pistons of a hydraulic lever and the volume remains constant.

Question 6

Archimedes’ Principle

Answer 6

The buoyant force of a body in liquid is equal to the weight of liquid displaced by the body. Focus on the volume submerged.

Question 7

Adhesion

Answer 7

Attractive force between liquid molecules and the molecule of another substance.

Question 8

Cohesion

Answer 8

Attractive force between the liquid molecules feel with the other molecules.

Question 9

Streamline

Answer 9

Path no turbulent liquid molecules take.

Question 10

Continuity Equation

Answer 10

Av = k

Mass flow rate of liquid remains constant throughout the tube.

Question 11

Bernoulli’s Equation

Answer 11

Conservation of energy in fluid flow says that increased velocity (decreased cross section) means decreased pressure at constant height.
P + 1/2ρv^2 + ρgy = k

Question 12

Viscosity

Answer 12

The internal friction of a fluid.

Question 13

Laminar Flow

Answer 13

The sliding of thin layers of liquid over each other as long a the flow rate remains below critical velocity.

Question 14

Turbulent Flow

Answer 14

Random local vortices that occur beyond the boundary layer of liquids.

Question 15

Young’s Modulus

Answer 15

Solid elasticity characterized by the ratio of stress (F/A) to strain (ΔL/L) when the force is perpendicular to the surface area.

Question 16

Shear Modulus

Answer 16

Solid’s resistance to shear stress as described by the ratio of shear stress (F/A) to strain (x/h) that occurs when force is parallel to the surface area.

Question 17

Bulk Modulus

Answer 17

The change in pressure to the change in volume.

B = ΔP/(ΔV/V)