"Tim Streater" wrote in message
.. .
In article , Brian Reay
wrote:

Certainly if you are analysing a problem and checking the dimensions (a
useful technique, not always taught these days although I made a point of
teaching it), indice notation is probably far easier to use.

I agree about the usefulness of dimensional analysis.

If I can't quite remember a formula, I use dimensional analysis. Is the
dimension that the formula produces different to the dimension of the answer
that I would expect? Am I adding together terms which are not the same
dimension? If so, check that I've remembered the formula correctly.

v^2 = u^2 + 2 as

m^2.s^-2 = m^2.s^-2 + m.s^-2 . m [ie m^s.s^-2]


So if I had brainfade and mis-remembered it as v^2 = u + 2as, I'd soon
realise that something was wrong.


Likewise with

s = ut + 1/2 at^2

m = m.s^-1 . s [ie m] + m.s^-2 . s^2 [ie m]