Physics · MECHANICAL PROPERTIES OF SOLIDS

In the stress-strain curve shown on page 2 (Fig. 8.2), which of the following correctly identifies the significance of the region between point A and point B, and the behaviour at point D?

1. A
   Region AB is non-linear yet elastic (stress not proportional to strain, but body regains dimensions when unloaded); point D corresponds to the ultimate tensile strength
2. B
   Region AB exhibits plastic deformation; point D is the fracture point
3. C
   Region AB is non-linear but fully plastic; point D is the yield point
4. D
   Region AB obeys Hooke's law; point D represents the elastic limit