Thread: Very simple question View Single Post
 Sci Advisor HW Helper Thanks P: 26,160 actually, there are units which are confusing in this way … eg the resistivity, ρ, of a material (also conductivity, permittivity, permeability) (by "a material", i mean eg copper, as opposed to a particular copper wire) ρ is measured in ohm-metres (Ω-m), but it's really Ω-m2 per m … because resistance R = ρl/A (l = length of the wire, A = cross-section area) calling it Ω-m is confusing! however, the combining of length and area (in resistivity) is different to the second-squared in acceleration … in resistivity, we can change l and A separately (the are two different measurements), so arguably they deserve to be mentioned separately in the units but in acceleration, the second-squared only involves one measurement, so there's no confusion