When we write a physical equation as a
function of its magnitudes, we are writing its dimensional
equation.
When we look at a dimensional equation we
can see if the physical equation from which it comes is incorrect.
You just have to write the dimensional equation of each side and see if
they are equal or not. If they are not we can state that the physical
equation is incorrect.
If you go through the following animation you will understand this more
clearly.
