Test 1

### In a venturi tube the area A1 = 100cm^2, Velocity V1 = 10cm/sec. What is the velocity V2 at point 2 if the area A2 = 10cm^2? What is the flow in cc/sec?

100cm/sec, 1000cc/sec

A1 x V1 = A2 x V2

100 x 10 = 10 x X, solve for X

X = 100cm/sec

Flow = A1 x V1

100 x 10 = 1000cc/sec

### What are the SI units of Tension? Remember T=PR/2. Where T = Tension, P = Pressure, R= Radius

Kg / (sec^2)

### What is the apparent weight of a sphere that is 10Kg in mass with a radius of 0.1 meters? Volume of a sphere is (4/3)pi*r^3. Spc gravity of water is 1gm/cm^3 or 1000Kg/m^3.

57 Newtons

10Kg = 10,000gm and 102gm = 1 newton

10,000 / 102 = 98 newtons

(4/3)**pi**10^3 = 4,188

4188 / 102gm = 41 newtons of water

So, 98 - 41 = 57 newtons to weight

### Cyclopropane has a velocity of 1.0m/sec through a tube diameter of 1.0cm into a diameter of 0.01cm. What is the Velocity change? What is the Pressure drop? Cyclopropane density is 1.8kg/m^3.

1x10^4 m/sec, -9x10^7 pascals

As Velocity increases Pressure will Drop.

### Force Equation (phAg)

p**v**g = pressure or phAg

p = Density

v = Volume (Ah or Area x Height)

g = Gravity

### Flow Equations. 3 of them

V1 x A1 = Flow

Velocity x Area = Flow

or

(Mass or Volume) / Time

or

Pressure / Resistance = Flow

### You are handed 5cc of 40mg/cc dopamine to mix in 245cc of NS. What is the final concentration in mcg/cc?

1. 40mg x 5cc = 200mg/cc

2. Convert to mcg 200mg x 1000mcg = 200,000mcg

3. 200,000mcg / 245cc NS = 816.32mcg/cc

### You are ventilating a patient and you analog pressure gauge reads 20cm H2O. What is the pressure in pascals?

1. There are 1.36mmHg in 1mm H2O

2. 20cmH2O / 1.36mmHg = 14.7mmHg

3. There are 760mmHg in 1 atmosphere

4. 14.7mmHg / 760mmHg = 0.01934mmHg

5. There are 100,000 pascals in 1 atms

6. 0.01934 x 100,000 = 1934 pascals

###
Given Poiseuille's law:

Q = [(pi**r^4**Delta P) / (8**n**l)]

What statement is true?

Flow is directly proportional to the 4th power of the radius.