On Aug 20, 2006, at 3:09 PM, Phil Richards wrote:
On 2006-08-20, Matthias Troyer <troyer@itp.phys.ethz.ch> wrote:
On Aug 19, 2006, at 2:04 PM, Andy Little wrote:
I was taught at school to do dimensional analysis checks manually. For example force = mass * acceleration; M = mass L = length T = time; force == M * L / T^2 acceleration = L/T^2 Therefore (M* L/T^2) = (M) * ( L/ T^2) In this case its just dimensional math, no value is involved. This is just a check of units. I would prefer calling them units and not quantities
Nope, it's a check of dimensionality, not units.
A check of units would be one that found an error in: m/s = ft/min
The difference between units and dimensionality incorrectness is that units can be converted (if they are compatible). They are (sometimes) compatible when their dimensionality is the same.
If your dimensionality is incorrect, you are screwed.
phil, back to my rock to hide under
OK, then it checks dimensions, but still not quantities