Chapter 5 : Pressure

Example 5.1 Page no.109

In [6]:
# Variables
P = 60 ;         #[Gpa]

# Calculation and Results
#(a)
p_atm = (P*(10**6))/101.3 ;           #[atm]
print '(a) Pressure in atmospheres is %.2e atm'%p_atm

#(b)
p_s = (P*(10**6)*14.696)/101.3 ;      #[psia]
print ' (b) Pressure in psia is %.2e psia'%p_s

# (c)
p_in = (P*(10**6)*29.92)/101.3 ;      #[inches of Hg]
print ' (c) Pressure in inches of Hg is %.2e in. Hg'%p_in

# (d)
p_mm = (P*(10**6)*760)/101.3 ;        #[mm of Hg]
print ' (d) Pressure in mm of Hg is %.2e mm Hg'%p_mm

(a) Pressure in atmospheres is 5.92e+05 atm
 (b) Pressure in psia is 8.70e+06 psia
 (c) Pressure in inches of Hg is 1.77e+07 in. Hg
 (d) Pressure in mm of Hg is 4.50e+08 mm Hg

Example 5.2 Page no. 110

In [1]:
# Variable
b_rd = 28.0 ;       #[in. Hg]
p_rd = 51.0 ;       #[psia]

# calculation
p_atm = b_rd*14.7/29.92 ;       # [psia]
p_tnk  =  p_atm+p_rd ;          #[psia]

# Result
print ' Pressure in tank in psia is %.1f psia'%p_tnk

 Pressure in tank in psia is 64.8 psia

Example 5.3 Page no. 111

In [2]:
# Variables
b_rd = 100.0 ;             #[kPa]
gp =  64.5*101.3/76.0 ;    #[kPa]

# Calculations
p_tnk = b_rd-gp ;          #[kPa]

# Results
print ' Absolute Pressure in tank in is %.1f kPa'%p_tnk
print '  Since absolute pressure in tank(%.1f kPa) is less than 20 kPa , the \
 mice probably will not survive. '%p_tnk

 Absolute Pressure in tank in is 14.0 kPa
  Since absolute pressure in tank(14.0 kPa) is less than 20 kPa , the  mice probably will not survive.

Example 5.4 Page no. 115

In [3]:
# Variables
df = 1.10*10**3 ;              #[kg/m**3]
d = 1.0*10**3 ;                #[kg/m**3]
g = 9.8 ;                      #[m/s**2]
h = 22.0 ;                     #[mm]

# Calculation
dP = (df-d)*g*(h*10**(-3)) ;   #[Pa]

# Result
print 'Pressure difference across the orifice plate is %.1f Pa.'%dP

Pressure difference across the orifice plate is 21.6 Pa.

Example 5.5 Page no. 117

In [4]:
# Variables
p_atm=730.0*29.92/760.0 ;            #[in. Hg]
gp= (4.0*29.92)/(2.54*12*33.91) ;    #[in. Hg]

# Calculation
p_air=p_atm-gp ;                     #[in. Hg]

# Result
print ' Pressure of the air is %.1f in. Hg.'%p_air

 Pressure of the air is 28.6 in. Hg.
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