Question

The symmetry of the stress tensor at a point in a body when at equilibrium is obtained from

• A. conservation of mass
• B. force equilibrium equations
• C. moment equilibrium equations
• D. conservation of energy

Answer 1

The correct option is C moment equilibrium equations

Consider rectangular block of unit thickness


Taking moment about $D$
${\tau }_{xy}.dy.1.dx={\tau }_{xy}.dx.1.dy$
${\tau }_{xy}={\tau }_{yx}$