Units (metric sytem)

l (distance)- m
t (time)- s
m (mass)- kg
a (area)- m^2
v (velocity)- m/s
D (density)- kg/m^3
g (gravity)- m/s^2
F (force)- N- kg m/s^2
E (energy)- J- kg m^2/s^2
P (power)- W- kg m^2/s^3