Slide 2 of 14
Notes:
The fact that strain means relative change in shape or size implies that it is dimensionless and has no units.
Stress, on the other hand, has dimension of force per unit area, or, less often, force per unit length.
This statement of Hooke’s Law (stress proportional to strain) is a more general statement than the more specific one given in a later slide, that restoring force is proportional to displacement.
