تانسور

right|thumb|300px|The second-order Cauchy stress tensor \mathbf{T} describes the stress experienced by a material at a given point. For any unit vector \mathbf{v}, the product \mathbf{T} \cdot \mathbf{v} is a vector, denoted \mathbf{T}(\mathbf{v}), that quantifies the force per area along the plane perpendicular to \mathbf{v}. This image shows, for cube faces perpendicular to \mathbf{e}_1, \mathbf{e}_2, \mathbf{e}_3, the corresponding stress vectors \mathbf{T}(\mathbf{e}_1), \mathbf{T}(\mathbf{e}_2), \mathbf{T}(\mathbf{e}_3) along those faces. Because the stress tensor takes one vector as inpu