Fundamental Quantities

Fundamental Quantities

SI unit

English Unit

Time

second (s)

second (s)

Mass

kilogram (kg)

slug sl ug

1 slug = 14.6 kg

Length

meter (m)

foot (ft)

1 ft = 0.305 m

Force

Newton (N)

pound (lb)

1 lb = 4.45 N

Energy

Joule (J) [W-s, Nm]

foot-pound (ft-lb) British Thermal Unit (BTU)

1 ft-lb = 1.36 J 1 BTU = 1055 J

Power

Watt (W) [J/s]

horsepower (hp)

1 hp = 746 W

Moment of intertia

(kg-m�)

(slug-ft �)

Torque

Newton-meter (Nfoot-pound (ft-lb) m)

Voltage

Volt (V)

Volts (V)

Charge

Coulomb (C)

Coulomb (C)

Current

Amperes (A=C/s)

Amperes (A)

Absolute Temperature

Degrees Kelvin (°K)

Degrees Rankine (°R)

1 °R = 9/5 °K

Common Temperature Scales

Degrees Celsius (°C)

Degrees Fahrenheit (°F)

°F = °Cx9/5+32 °C = °K-273.15 °F = °R-459.67

 Linear Mechanical Systems

Spring Constant

(N/m)

(lb/ft)

Friction Coefficient

(N-s/m)

(lb-s/ft)

 Rotating Mechanical Systems

Spring Constant

(N-m/rad)

(ft-lb/rad)

Friction Coeffiicient

(N-m-s/rad)

(ft-lb-s/rad)

Thermal Resistance

°K/W

s-°R/BTU

Thermal Conductance

W/°K

BTU/(s-°R)

Thermal Systems

Thermal Capacitance, or J/°K Thermal Mass

BTU/°R

 Electrical Systems

Electrical Resistance

Ohm-Ω Ohm- Ω (V/A)

Ohm-Ω Ohm-Ω (V/A)

Conversion

1 slug-ft� = 1.36 Nm� 1 ft-lb = 1.36 N-m

Electrical Conductance

Siemens-S (A/V)

Siemens-S (A/V)

Capacitance

Farad-F (C/V)

Farad-F (C/V)

Inductance

Henry-H (V-s/A)

Henry-H (V-s/A)

Prefixes

Prefix Quantities

Symbol Multiplier

pico

p

10

-12

nano

n

10

-9

micro

μ

10

milli

m

10

-3

centi

c

10

-2

deci

d

10

-1

kilo

k

10

+3

mega

M

10

giga

G

10

tera

T

10

-6

+6 +9 +12