# Chapter 1 : Introduction and Basic Concepts¶

### Example 1.1, Page no:5¶

In :
# Variables
F = 300; 			    #[N]
g_local = 4.5; 			#local gravitational acceleration[m/s**2]
g_earth = 9.81; 		#earth's gravitational acceleration[m/s**2]

# Calculations
#To find man's mass and weight on earth
m = F/g_local;			#mass of man[kg]
w = m*g_earth; 			# weight of man on earth[N]

# Results
print 'Mass of man is %f kg'%m
print '\nWeight of man on earth is %f N'%w

Mass of man is 66.666667 kg

Weight of man on earth is 654.000000 N


### Example 1.2, Page no:6¶

In :
# Variables
p1 = 1.15*10**5; 			#measured pressure[N/m**2]
p2 = 1.01325*10**5; 		#atmospheric pressure[N/m**2]
rho = 2.95*10**3; 			#specific gravity of fluid
g = 9.8067

# Calculations
#To find height of manometer fluid
p = p1-p2; 	     		#difference in pressure
h = p/(rho*g); 			#height of manometer fluid[m]

# Results
print 'Height of manometer fluid is %f m'%h

Height of manometer fluid is 0.472697 m


### Example 1.3, Page no:8¶

In :
# Variables
PE = 1.5*10**3; 	#potential energy[J]
m = 10; 			#mass in kg
u = 50; 			# velocity in m/s
g = 9.8067

# Calculations
h = PE/(m*g);			# height from ground in m
#Using equation 1.9 (Page no. 8)
KE = 0.5*m*(u**2);			# Kinetic energy in J

# Results
print 'Height from ground is %f m'%h
print '\nKinetic Energy of body is %3.2e J'%KE

Height from ground is 15.295665 m

Kinetic Energy of body is 1.25e+04 J


### Example 1.4, Page no:9¶

In :
# Variables
#Given
F = 600.; 			#weight in N
t = 120.; 			#time in sec
h = 0.18; 			#height of stairs in m

# Calculations
#To determine the power developed in man
S = 20*h; 			#total vertical displacement in m
W = F*S; 			#work done in J
P = W/t; 			#power developed

# Results
print 'Power developed is %i W'%P

Power developed is 18 W


### Example 1.5, Page no:9¶

In :
import math

# Variables
#Given:
A = (math.pi/4)*(0.1**2); 			#area in m**2
P = 1.01325*10**5; 			#pressure in N/m**2
m = 50; 			#mass of piston and weight in kg
g = 9.81; 			#acceleration due to gravity (N/m**2)

# Calculations and Results
#To determine the force exerted pressure work done and change in potential energy
#(a)
Fa = P*A; 			#force exerted by atmosphere in N
Fp = m*g; 			#force exerted by piston and weight in N
F = Fp+Fa; 			#total force exerted in N
print 'Total force exerted by the atmosphere, the piston and the weight is %f N'%F

#(b)
Pg = F/A; 			#pressure of gas in N/m**2
print 'Pressure of gas is %5.4e N/m^2'%Pg

#(c)
S = 0.4; 			#displacement of gas in m
W = F*S; 			#work done by gas in J
print 'Work done by gas is %f J'%W

#(d)
PE = m*g*S; 			#change in potential energy in J
print 'Change in potential energy is %f J'%PE

Total force exerted by the atmosphere, the piston and the weight is 1286.304689 N
Pressure of gas is 1.6378e+05 N/m^2
Work done by gas is 514.521876 J
Change in potential energy is 196.200000 J


### Example 1.6, Page no:10¶

In :
import math

# Variables
#P =(2*10**5)*D
Df = 2.5; 			#final diameter (m)
Di = 0.5; 			#initial diameter(m)

# Calculations
#To determine work done by gas
W = (math.pi/4)*10**5*((Df**4)-Di**4);

# Results
print 'Work done by gas is %6.4e J'%W

Work done by gas is 3.0631e+06 J


### Example 1.7, Page no:19¶

In :
# Variables
T = 300.; 			    #temperature in K
P = 6.5*10**5; 			#pressure in N/m**2
Pa = 1.01325*10**5; 	#atmospheric pressure in N/m**2
R = 8.314; 			    #ideal gas constant
m = 2.; 			    #mass of gas (kg)
M = 44.; 			    #molecular weihgt of gas

# Calculations
#To find the work done on surrounding
n = m/M; 			            # n is number of kmoles
Vi = (n*R*10**3*T)/P; 			# initial volume in m**3
Vf = 2*Vi; 		            	#final volume in m**3
V = Vf-Vi; 			            #change in volume
Ps = Pa+(5000*9.8067); 			#pressure on surroundings
W = Ps*V; 			            #work done on the surroundings

# Results
print 'Work done on surroundings is %5.2e J'%W

Work done on surroundings is 2.62e+04 J

In :
import math
from scipy import integrate

#Taking 3rd and 2nd order derivative respectively, we get the following expression
#x = ((2*10**5*math.pi)/2)*
D = lambda x: x**3

9.75