Rigidity

Rigidity is that property possessed by a solid which causes it to experience no deformation or strain when a stress is applied to it. The fraction

strain infinitely great. No substance is. however, perfectly rigid. Every substance yields under the action of a stress if we take small enough masses of them, such as thin wires; but some solids, such as steel, have a very large co-efficient of rigidity, and unless a considerable stress is applied to them the corresponding strain is too small to be observed.