Moment of resistance (MR) = Z × f
= bd² / 6 × 15
= 96 ×10⁶ Nmm.

Here, b = 200 mm; d = 40mm
y = 40/2 = 20 mm
f = 80N/mm²
From relation; E/R = f/y
R = E×y / f
= 80000×20 / 80
= 20000mm = 20m.

A beam is said to be a strength when maximum induced bending and shear stresses are within safe permissible stresses stiffness of a beam is a measure of its resistance against deflection.

The moment of couple with resists action of bending moment is a moment of resistance and flexural strength possessed by section is moment of resistance offered by it.

The moment resisting capacity of cross section of a beam is termed as strength of beam. The bending stress is maximum at extreme fibres of cross section. The strength of two beams of same material can be compared by sectional modulus values.

When a load acts on a body, re is deformation of body which causes movement of applied load. Thus work is done is stored in body as energy and load is removed this stored energy which is by virtue of strain is called resilience.

By two equations; we have e = y/R & e = f/E
Equating both equations; we get e = f/E = y/R
Hence stress (f) is directly proportional to distance from neutral axis(y).

The ratio of moment of inertia to distance to extreme fibre is called modulus of section or section modulus. It is generally denoted by letter Z. Section modulus is expressed in m³
Z = I/y
= m⁴/ m
= m³.

A creep is a plastic deformation underweight strain of material where is under constant stress this is one of mechanical properties of engineering materials. The best example is failure of concrete.

Strain energy stored in body be ?U? = f²/ 2 E × Volume.
= 100²/ 2×2×10⁵
= 0.05 kNm.