I am very keen to have consistent standards of notation and terminology across this site. Its hard enough to learn these things without being confused by inconsistent standards. It may not be perfect yet so, if you find any inconsistencies across the site please let me know.
The units used are based on the international system of units (SI units) which has 3 primary units as discussed on this page. I have also tried to apply standards to the mathematical notation and terminology (see mathematical standards).
Here are some of the notations for physical quantities:
Dimensions
symbol 
description 
type 
units 
web page 
l 
length 
vector 
m 
definition 
cm 
position of centre of mass of object 
vector 
m 
definition 
r 
position of particle relative to object 
vector 
m 
definition 
p 
position of particle in absolute coordinates 
vector 
m 
definition 
t 
time 
scalar 
s 
definition 
d … /dt 
rate of change 
scalar 
s^{1} 
definition 
Δt 
time between frame n and frame n+1 
scalar 
s 
definition 
f 
frequency 
scalar 
s^{1} 
definition 
ω 
angular velocity 
bivector 
s^{1} 
definition 
angle 
angle in radians 
scalar 
none 
definition 
Matter
symbol 
description 
type 
units 
web page 
m 
rest mass 
scalar 
kg 
definition 
mi 
mass of particle i 
scalar 
kg 
definition 
mt 
total mass 
scalar 
kg 
definition 
ρ 
density 

kg m^{3} 

Forces
symbol 
description 
type 
units 
web page 
F 
Force 
vector 
N=newton=kg*m/s^{2} 
definition 
P 
effort 
vector 
N=newton=kg*m/s^{2} 
definition 
W 
load 
vector 
N=newton=kg*m/s^{2} 
definition 
b 
static friction 
vector 
N=newton=kg*m/s^{2} 
definition 
moment 
effort 
bivector 
Nm=newtonmetre=kg*m^{2}/s^{2} 
definition 
p 
pressure 

kg m^{1} s^{2} 

Kinematics
symbol 
description 
type 
units 
web page 
x(t) 
distance as a function of time 
vector 
m 
definition 
x_{i} 
initial position 
vector 
m^{} 
definition 
x_{f} 
final position 
vector 
m 
definition 
v(t) 
linear velocity as function of time 
vector 
m/s 
definition 
v_{i} 
initial velocity (sometimes denoted by u) 
vector 
m^{} 
definition 
v_{f} 
final velocity 
vector 
m 
definition 
c 
speed of light 
scalar 
m/s 
definition 
ω 
angular velocity vector 
bivector 
s^{1} 
definition 
a 
linear acceleration 
vector 
m/s^{2} 
definition 
α 
angular acceleration 
bivector 
s^{2} 
definition 
Dynamics
symbol 
description 
type 
units 
web page 
E 
energy 
scalar 
kg m^{2}/s^{2} = N m 
definition 
P 
power 
scalar 
kg m^{2}/s^{3} = N m/s 
definition 
p 
linear momentum 
vector 
kg m/s = N s 
definition 
L 
angular
momentum 
bivector 
kg m^{2}/s = N m s 
definition 
[I] 
inertia tensor (moment of inertia)
Matrix representation:
[I] = 
∫(r_{z}²+r_{y}²)dm 
∫r_{x}*r_{y}dm 
∫r_{x}*r_{z}dm 
∫r_{y}*r_{x}dm 
∫(r_{z}²+r_{x}²)dm 
∫r_{y}*r_{z}dm 
∫r_{z}*r_{x}dm 
∫r_{z}*r_{y}dm 
∫(r_{x}²+r_{y}²)dm 


tensor 
kg m^{2}= N m s^{2} 
definition 
H 
the instantaneous angular momentum
about PC 
bivector 
kg m^{2}/s = N m s 
definition 
F 
net force 
vector 
kg m/s^{2} = N 
definition 
T 
torque 
bivector 
kg m^{2}/s^{2} = N m 
definition 
h 
m * s = mass times distance 
vector 
Kg m = N s^{2} 
definition 
J 
impulse 
vector 
kg m/s= N s 
definition 
Terminology
Scalar
I have used the term 'scalar' interchangeably with the term 'real', that is, a continuous value that can be represented by a single number.
Strictly speaking the term 'scalar' should be reserved for a quantity that is used to scale a vector, that is change its magnitude without changing its direction, or in other words a scalar is the ratio of parallel vectors.
For instance I should not really call energy a scalar because there are no vectors involved.
I apologise for my lack of mathematical rigor here, its just that the word scalar seems to better express that it is not a vector and its less likely to cause confusion with the real part of a complex number. Also this (mis?)usage is quite common in the computer world.
This site may have errors. Don't use for critical systems.