# Chapter 1 : Introduction¶

## Example 1.1 pg : 22¶

In [1]:

# Variables
import math
d = 8. 			#in
ir = 16. 			#in
MW = 28.97
T = 70.+460 			#R
P = 30+14.7 			#psia

# Calculations
V = math.pi**2 *d**2 *(d+ir)/4
V = V*10./12**3
Rair = 1545/MW
m = P*144*V/(Rair*T)

# Results
print "Mass of air  =  %.2f lbm"%(m)

Mass of air  =  4.99 lbm


## Example 1.2 pg : 22¶

In [2]:

# Variables
V = 4. 			#in**3
P = 30. 			#psia
T = 500.			#R
MW = 32.

# Calculations
print ("Metric unit conversion,")
V = V*2.54**3 *10**-3
P = 30*4.448/(2.54**2 *10**-4)
T = 5*(T-32)/9 +273
n = P*V/(8314.5*T)
eta = n*1000
N = eta*6.025*10**23
m = eta*MW

# Results
print "No. of molecules of oxygen  =  %.3e molecules"%(N)
print " Mass of molecules  =  %.1f g"%(m)

#The answer in the textbook is a bit different due to rounding off error

Metric unit conversion,
No. of molecules of oxygen  =  1.843e+24 molecules
Mass of molecules  =  97.9 g


## Example 1.3 pg : 26¶

In [3]:

# Variables
import math
P = 14.7 			#psia
T = 70.+460 			#R
M = 32.

# Calculations
Ro = 1545/M
V2 = 3*Ro*T
V2 = V2*32.174
vrms = math.sqrt(V2)

# Results
print "rms velocity  =  %d ft/sec"%(vrms)

rms velocity  =  1571 ft/sec