The physical law
is unit free if it for all positive 
holds that
if and only if
where qi are definied as in the previous part.
Example: The physical law
is unit free.
Proof: If we put
we get
since
The law thus becomes
that is,
Remark: If x is given in centimeters and x is given in meters, we have that
If t is given in seconds and t in minutes, we have that
In this case, g is given in m/(min)2.