Note that the spring constant k = ea0 l0 k = e a 0 l 0 where e is the young's modulus of the material (constant, at least in one direction), a0 a 0 is the unstretched cross sectional area, and l0 l 0 is the รขโ‚ฌยฆ So, k k must have dimensions of nรขโ€น. M2 c2 n m 2 c 2 as well as having a numeric value.

Consider the statcoulomb. In gaussian units the unit of charge is defined such รขโ‚ฌยฆ