## IntroEdit

**What is a fluid?**

- A substance that flows. Liquids and gases.

## DensityEdit

**What is the key difference between fluid mechanics and Newtonian mechanics?**

- Whereas Newtonian mechanics was concerned with mass (F=ma), fluid mechanics is concerned with density, ρ.

**What is the formula for denisty?**

- ρ = mass/volume

**What is the specific gravity of a substance?**

- sp. gr. = ratio of the density of any substance to the density of water. = ρ
_{substance}/ρ_{water}

**What is the density of water?**

- 10
^{3}kg/m^{3}

## PressureEdit

**What is the formula for pressure?**

- P = force
_{perp}/area

**What is the SI unit for pressure?**

- Pascal = Pa = N/m
^{2}

**What is P _{atm}?**

- 10
^{5 Pa }

## Hydrostatic PressureEdit

**What is the force of a column of liquid above a sheet of l*w? What is the pressure?**

- F = mg = (ρV)g = ρ(lwh)g
- P = F/A = F/lw = ρhg = ρgh

**Does the shape of the container matter in determining pressure?**

- No. P = ρgh. Only density and height matter. The liquid flows around any changes in shape.

**What is the total/absolute pressure?**

- P
_{total}= P_{above liquid}+P_{liquid}= P_{0}+ρgh

**What is the gauge pressure?**

- P
_{gauge}= P_{total}- P_{atm}= ρgh. The gauge reads just the internal pressure, as P_{atm}is acting on the gauge as well.

**Does |pressure| change with direction?**

- Nope. Pressure always pushes perpendicular to the area. P = ρgh, no term for orientation of the thing.

## BuoyancyEdit

**What is the basis of buoyancy?**

- The underside of the object is submerged deeper, thus more P = ρgh. So an upward force is created.

**What is Archimedes' principle? (Words & formula)**

- The buoyant force, F
_{buoy}, is equal to the weight of the fluid displaced by the object. - F
_{buoy}= ρ_{fluid}V_{submerged}g

**What is the relationship of forces when an object floats?**

- mg = F
_{buoy}= ρ_{fluid}V_{submerged}g = ρ_{objectVobjectg } - V
_{submerged}/V_{object}= ρ_{object}/ρ_{fluid}

**What happens when ρ _{object} >/=/< ρ_{fluid}?**

- If ρ
_{obj}< ρ_{fluid}, then it will float, as ρ_{obj}/ρ_{fluid}< 1, so V > V_{submerged}. If ρ_{obj}= ρ_{fluid}, then V = V_{submerged}, and the object will be neutral. And if ρ_{obj}> ρ_{fluid}, then V < V_{submerged}, it will sink.

**How do you find the apparent weight of a submerged object?**

- F
_{g}-F_{buoy}= N - F
_{buoy}= ρVg

## Flow Rate and The Continuity EquationEdit

**What is flow rate?**

- Q = flow rate = Av. Amount of fluid in volume that flows past a give point per second.

**Flow rate vs flow speed?**

- Flow rate is volume/time, flow speed is length/time.

**What is (the basis of) the Continuity Equation?**

- Q
_{1}= Q_{2}= A_{1}v_{1}= A_{2}v_{2}

## Bernoulli's EquationEdit

**What are the assumptions of the Bernoulli equation?**

- Fluid is incompressible, no viscosity, and flow is streamline.

**What is viscosity?**

- Internal friction for fluids.

**What is streamline?**

- Inject dye and form lines in the stream. If they do no cross then = streamline.

**What is Bernoulli's Equation?**

- P
_{1}+ρgy_{1}+(1/2)ρv_{1}^{2}= P_{2}+ρgy_{2}+(1/2)ρv_{2}^{2} - Similar to conservation of energy. mgh similar to ρgy, and (1/2)mv
^{2}similar to (1/2)ρv^{2}

### Torricelli's TheoremEdit

**What is efflux speed?**

- Punch a hole in a barrel. How fast the water comes out.

**What is the derivation of Torricelli's Theorem?**

- Start from Bernoulli's equation.
- Point 1 at the top, point 2 at the hole. P
_{1}= P_{atm}= P_{2}; because both are open to air. - A
_{1}<< A_{2}, so v_{1}<< v_{2}. Call v_{1}about 0. - ρgy
_{1}= ρgy_{2}+ ρv_{2}^{2} - v
_{2}= sqrt(2g(y_{1}-y_{2})) = sqrt(2gh)

### The Bernoulli EffectEdit

**What is (the derivation of) the Bernoulli Effect?**

- Combo of flow rate and Bernoulli's equation. P
_{1}+(1/2)ρv^{2}= P_{2}+(1/2)ρv_{2}^{2} - ↑A → ↓V → ↑P.
- Think of it as fast moving stuff has less energy to create pressure with. Stuff moving has lower average density.