Basic Systems of Dimensions
è 3 basic systems of dimensions and units
(1) International System (SI)
MKS system
Units
Primary dimensions
Length
[L]
Mass
[M]
Time
[T]
Temperature [𝜃]
Force
meter
(m)
kilogram (kg)
second
(s)
Kelvin
(K)
[F]
Newton
Secondary
dimension
(2) British Gravitational (BG)
Length
Force
Time
Temperature
Mass
Secondary
dimension
(N)
1 N = 1 kg.m.s-2
Primary dimensions
[L]
[F]
[T]
[𝜃]
[M]
CGS system
centimeter (cm)
gram
(g)
second
(s)
Kelvin
(K)
dyne
(dyn)
1 dyn = 1 g.cm.s-2
(3) English Engineering (EE)
Primary dimensions
Units
foot
pound force
second
Rankine
slug
(ft)
(lbf)
(s)
(R)
(slug)
1 slug = 1 lbf.s2.ft-1
Length
Mass
Force
Time
Temperature
[L]
[M]
[F]
[T]
[𝜃]
Temperature units
Units
foot
(ft)
pound mass (lbm)
pound force (lbf)
second
(s)
Rankine
(R)
R = °F + 459.67
K = °C + 273.15