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L
0
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L
1
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L
2
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L
3
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L
4
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L
5
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T0
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lenght
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surface
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volume
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T-1
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frequency
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speed
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flow
rate
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|
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T-2
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(frequency)²
|
acceleration
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T-3
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T-4
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T-5
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We
can see above, in the table, the dimensions of some physical quantities
:
In the first line we find the different exponents of L, which are
Lo, L1 , L2 , L3 , L4, L5, L6
In the first column to the left we can see the negative exponents of T,
which are T0, T -1 , T -2 , T -3 , T -4 , T -5
- Distance
or length (L dimension) in L1T0
- Surface
(dimension L²) in L2 T0
- Volume
(dimension L³) in L3 T0
- Velocity
(dimension L / T) in L1 T - 1
- Acceleration
(dimension L / T ²) in L1 T - 2
- Frequency
(dimension 1 / T) in L0 T - 1
We also
have:
- The square of
frequency (dimension 1 / T ²) in L0 T - 2
- Flow = volume
per second (dimension L³ / T) in L³ T - 1
Mass
= L³ / T²
|
L
0
|
L
1
|
L
2
|
L
3
|
L
4
|
L
5
|
T0
|
|
longueur
|
surface
|
volume
|
|
|
T-1
|
frequency
|
speed
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|
flow
rate
|
|
|
T-2
|
(frequency)²
|
acceleration
|
|
mass
|
|
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T-3
|
|
|
|
|
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T-4
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T-5
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,A unitary mass m
subject, in space, to an acceleration of 9,81 m/s (inside a rocket, for
example) undergoes the same F force that it would undergo when
it is subject to the earth's attraction.
Those two forces
are of the same nature (in principle identical, nothing can distinguish
them from each other), therefore they should have the same dimensions.
Consequently, here we consider inertial mass and gravitational mass to
be the exact same.
F = ma with
dimensions M . L / T² (1)
F = K.m.Mt / Rt² with dimensions M² / L² (2)
With Mt being the
earth's mass (of dimension M) and Rt the earth's radius (of dimension
L)
Comparing (1) and (2)'s
dimensions we have M . L / T² = M² / L²
Therefore the dimensions
of mass will be M = L³ / T² ( see
appendix 1 )
From that we can express the mass in kg or as m³ / s² (see appendix
2 )
In (2) the Newton constant K is considered
simply as a number without any dimension.
Some
other measurable quantities:
|
L
0
|
L
1
|
L
2
|
L
3
|
L
4
|
L
5
|
T0
|
constant
|
lenght
|
surface
|
volume
|
|
|
T-1
|
frequency
|
speed
|
|
flow
rate
|
|
|
T-2
|
(frequency)²
density
|
acceleration
|
potential
|
mass
|
|
|
T-3
|
|
|
|
strenght
- viscosity
|
moment
|
action
|
T-4
|
|
|
pressure
temperature
|
stiffness
|
force
|
energy
- work
|
T-5
|
|
|
|
|
|
power
|
- Momentum
(mass . velocity) in L4 T -3
- Force
(mass . acceleration) in L4 T -4
- Work
or energy (force . displacement) in L5 T -4
- Power
(energy/time) in L5 T -5
- Potential
(energy/mass) or (mass/distance) in L2 T -2
We also
have:
- Pressure
(force/surface) in L2 T -4
- Stiffness
of a spring (force/displacement) in L3T -4
- The square
of mass (mass . mass) in L6 T -4
- The square
of velocity (velocity . velocity) in L2 T -2
- The square
of frequency (frequency . frequency) in T -2
- Action
(energy . time) in L5 T -3
Some
fundamental relations in physics
M.a = F
( L3 T -2 )( L1 T -2 ) = ( L4 T -4 )
=> mass
. acceleration = force
M.v = p ( L3 T -2
)( L1 T -1 ) = ( L4 T -3 ) =>
mass
. velocity = momentum
M.v² = E ( L3 T -2 )( L2
T -2 ) = ( L5 T -4 ) =>
mass
. (velocity)² = energy
M/R² = a ( L3 T -2 )( L-2 )
= ( L1 T -2 )
=>
mass / (distance )² = acceleration ( g = Mt / R²
M²/R = E ( L3 T -2 )² (L-1)
= ( L5 T -4 ) => (mass)²
/ (distance) = energy
M²/R² = F ( L3 T -2 )² (L-2) =
( L4 T -4 ) =>
(mass)²
/ (distance)² = force
F.L = E (
L4 T -4 )( L ) = ( L5 T -4 ) =>
force
. distance = energy (work)
F / L = k ( L4 T -4 )(
L-1 ) = ( L3 T -4 )
=>
force / distance = stiffness (of a spring, for example)
k / M = T -2 ( L3 T -4 )( L-3 T 2 ) = ( L0 T -2 )
=>
stiffness / mass = square of frequency
F . v = W ( L4 T -4 )( L1 T
-1 ) = ( L5 T -5 ) =>
force . velocity = power
p / T = F ( L4 T -3 )( L0 T
-1 ) = ( L4 T -4 )
=>
momentum / time = force
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