Question

define shear stress and modulus of rigidity???

Answer 1

In materials science, shear modulus or modulus of rigidity, denoted by G, or sometimes S or μ, is defined as the ratio of shear stress to the shear strain: The derived SI unit ofshear modulus is the pascal, although it is usually expressed in gigapascals or in thousands of pounds per square inch

Answer 2

shear stress is a type of stress ,when deforming force is applied along the tangential plane of a body to cause change in shape of the body at constant volume ,the restoring force per unit cross sectional area is called shearing stress
therefore,shearing stress= restoring force/cross sectional area=F/A
modulus of rigidity is within elastic limit,the ratio of shearing stress to shearing strain is called shear modulus of elasticity.
neta=shearing stress/shearing strain.
neta =F/A/theta=F/Atheta
si unit is pascal or newton per meter square