Mechanics is harder.
Or, more accurately, in a 3 year engineering course it is possible to cover enough of the detail of structures theory to satisfy most practical professional problems (that is the theory you learn in uni, plus the codes, plus practical application, will suffice). Mechanics has never ending layers of complexity.
One reason for this is that most people who design structures are at the mercy of the builders etc, therefore things are not designed to the n'th degree. If I specified the breaking strength of a concrete to within +/- 15% I'd get laughed at, yet that is the worst variation in physical properties I routinely deal with in the mechanical world.
Cheers
Greg Locock
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