The deformation of a bar under its own weight = Wl^2 / 2E.
whereas Deformation under direct load = Wl^2 / E.
therefore The deformation of a bar under its own weight is half (1/2) the deformation if the same body is subjected to a direct load equal to the weight of the body.

Elongation of bar = (wl^2/2E).
Elongation of conical bar = (wl^2/6E).
Conical bar/Prismatic Bar.
= (wl^2/6E) / (wl^2/2E),
=1/3.

A strain gauge rosette is a term for an arrangement of two or more strain gauges that are positioned closely to measure strains along different directions of the component under evaluation.
Strain rosetters are used to measure linear strain.

The ultimate tensile stress for mild steel is more than the ultimate compressive stress.