Explain the bending equation M/I = σ/y = E/R and its assumptions.

The bending equation relates bending moment (M), moment of inertia (I), bending stress (σ), distance from neutral axis (y), Young's modulus (E), and radius of curvature (R). Assumptions include: material is homogeneous and isotropic, plane sections remain plane, Hooke's Law applies, beam is initially straight, and loads act in the plane of symmetry. It fails for large deflections or plastic bending.