The document provides a comprehensive overview of units, their definitions, and conversion factors, crucial for understanding measurements in various fields, particularly the petroleum industry. It covers fundamental units such as length, mass, time, force, moles, molecular weight, pressure, and temperature, detailing their SI, CGS, and English system counterparts. Additionally, it highlights the importance of these units and how they relate to derived quantities.

1. DEFINITION OF UNITS AND
THE CONVERSION
FACTORS
ABDELATY AMER

2. DEFINITION OF UNITS AND
THE CONVERSION FACTORS

1
Importance and Types of Units

2
Fundamental Units and Prefixes

Units of Mass. 3

4
Units of Length

5
Units of Time

..
6
Units of Force

.
7
Units of Moles

8
Units of Molecular Weigh

9
Units of Pressure

10
Units of Temperature

3. DEFINITION OF UNITS AND
THE CONVERSION FACTORS
1
Importance and Types of Units
The petroleum industry and its research began and grew
Mainly in the United States during the last century. The rela
-
tions developed in the 1930s, 1940s, and 1950s were mainly
graphical. The best example of such methods is the Winn

nomogram developed in the late 1950s [86]
.

4. DEFINITION OF UNITS AND
THE CONVERSION FACTORS
.
2
Fundamental Units and Prefixes
Generally there are four fundamental quantities of length (L)
,
mass (M), time (t), and temperature (T) and when their units
are known, units of all other derived quantities can be deter
-
mined. In the SI system, units of length, mass, and tempera
-

ture are meter (m), kilogram (kg)

5. DEFINITION OF UNITS AND
THE CONVERSION FACTORS
3Units of Mass
The mass is shown by m and its unit in SI is kg (kilogram), in
cgs is g (gram), and in the English unit system is Ibm (pound
-
mass). On many occasions the subscript m is dropped for lb

when it is referred to mass
.

6. DEFINITION OF UNITS AND
THE CONVERSION FACTORS
4
Units of Length
The unit of length in SI is meter (m), in cgs is centimeter
(
cm
,)
and in English unit system is foot (ft). Smaller values
of length in English system are presented in inch (in.). The

conversion factors are as follows
:

7. DEFINITION OF UNITS AND
THE CONVERSION FACTORS
.
5
Units of Time
The unit of time in all major systems is the second (s); how
-
ever, for large values of time other units such as minute (rain)
,
hour (h), day (d), and sometimes even year (year) are used
Appropriately. The conversion factors among these units are
as follows

8. DEFINITION OF UNITS AND
THE CONVERSION FACTORS
6
Units of Force
As mentioned above, the unit of force in the SI system is
Newton (N) and in the English unit system is pound-force
(
lbf
.)
1 lbf is equivalent to the weight of a mass of 1 lbm at
the sea level where the acceleration of gravity is 32.174 ft/s 2
(
9.807
m/s2
.)
In the cgs system, the unit of force is dyne (dyn)
.

Another unit for the force in the metric system is kgf
,