UNITS AND CONVERSION FACTORS
E.J. ROSCHKE
PROPULSION DIVISION
JET PROPULSION LABORATORY
1
, NOTE:
Many years ago I was given a copy of this document, prepared in handwriting, some time in
the early 1960’s. I did not know the author, E.J. Roschke. I have found it to be such a useful
reference that I decided to have an electronic version prepared. Recently, I spoke with Dr.
Roschke, now retired from the Jet Propulsion Laboratory to learn of the document’s origin. In
the early 1960’s a group of research engineers, largely having backgrounds in mechanical
engineering, were engaged in the new field of electric propulsion. They experienced practical
annoyances with the mingling of units from mechanical engineering, electrical engineering and
physics. That situation motivated Dr. Roschke to assemble this material.
Although I have carefully checked the values given here, it is quite possible that some
typographical errors remain. I will appreciate learning any corrections that should be made.
F.E.C. Culick
Mechanical Engineering
California Institute of Technology
October 2001
2
, UNITS AND CONVERSION FACTORS
Table of Contents
Section Page
References 3
I. Decimal Multiples and Submultiples 4
II. Description of Units
Mechanical, Electric, Magnetic 4
III. Equivalent Units mksq System 5
IV. Dimensions of esu and emu Electric
and Magnetic Quantities 5
V. Dimensions and Units for Physical Quantities — mksq System 6,7
A. Mechanical 6
B. Thermal 7
C. Electric and Magnetic 7
VI. Conversion of mksq Units to Gaussian Units 8
VII. Conversion Factors 8-23
A. Plane Angle 8
B. Solid Angle 8
C. Length 9
D. Area 9
E. Volume 9
F. Mass 10
G. Density 10
H. Time 11
I. Speed 11
J. Force 11
K. Pressure 12
L. Energy, Work, Heat 13
M. Specific Energy 14
N. Specific Energy Per Unit Temp. 15
O. Power 16
P. Heat Flux 17
Q. Heat Transfer Coefficient 17
R. Thermal Conductivity 18
S. Absolute Viscosity 19
T. Kinematic Viscosity 19
AA. Electric Charge 20
BB. Electric Current 20
CC. Electric Potential 20
DD. Electric Resistance 21
EE. Electric Resistivity 21
FF. Capacitance 21
GG. Inductance 22
1
E.J. ROSCHKE
PROPULSION DIVISION
JET PROPULSION LABORATORY
1
, NOTE:
Many years ago I was given a copy of this document, prepared in handwriting, some time in
the early 1960’s. I did not know the author, E.J. Roschke. I have found it to be such a useful
reference that I decided to have an electronic version prepared. Recently, I spoke with Dr.
Roschke, now retired from the Jet Propulsion Laboratory to learn of the document’s origin. In
the early 1960’s a group of research engineers, largely having backgrounds in mechanical
engineering, were engaged in the new field of electric propulsion. They experienced practical
annoyances with the mingling of units from mechanical engineering, electrical engineering and
physics. That situation motivated Dr. Roschke to assemble this material.
Although I have carefully checked the values given here, it is quite possible that some
typographical errors remain. I will appreciate learning any corrections that should be made.
F.E.C. Culick
Mechanical Engineering
California Institute of Technology
October 2001
2
, UNITS AND CONVERSION FACTORS
Table of Contents
Section Page
References 3
I. Decimal Multiples and Submultiples 4
II. Description of Units
Mechanical, Electric, Magnetic 4
III. Equivalent Units mksq System 5
IV. Dimensions of esu and emu Electric
and Magnetic Quantities 5
V. Dimensions and Units for Physical Quantities — mksq System 6,7
A. Mechanical 6
B. Thermal 7
C. Electric and Magnetic 7
VI. Conversion of mksq Units to Gaussian Units 8
VII. Conversion Factors 8-23
A. Plane Angle 8
B. Solid Angle 8
C. Length 9
D. Area 9
E. Volume 9
F. Mass 10
G. Density 10
H. Time 11
I. Speed 11
J. Force 11
K. Pressure 12
L. Energy, Work, Heat 13
M. Specific Energy 14
N. Specific Energy Per Unit Temp. 15
O. Power 16
P. Heat Flux 17
Q. Heat Transfer Coefficient 17
R. Thermal Conductivity 18
S. Absolute Viscosity 19
T. Kinematic Viscosity 19
AA. Electric Charge 20
BB. Electric Current 20
CC. Electric Potential 20
DD. Electric Resistance 21
EE. Electric Resistivity 21
FF. Capacitance 21
GG. Inductance 22
1
