It is given by the ratio of pressure applied to the corresponding relative decrease in the volume of the material. Mathematically, it is represented as follows: B = Δ P / ( Δ V / V ) Where: B : Bulk modulus Δ P : change of the pressure or force applied per unit area on the material Δ V : change of the volume of the material due to the compression V : Initial volume of the material.

Calculate the strain energy per unit volume in a brass wire of length 3 m and area of cross-section 0 . 6 m m 2 when it is stretched by 3 m m and a force of 6 k g w t is applied to its free end.

Here we use the strain energy formula as follows Strain energy = 1 2 × load × extension Strain energy per unit volume = e n e r g y v o l u m e = F Δ L L A = 6 × 9 . 8 × 3 × 10 - 3 3 × 6 × 10 - 7 = 9 . 8 × 10 4 J o u l e / m 3

Define Young’s modulus.

The mechanical property of a material to withstand the compression or the elongation with respect to its length. Mathematically, we have, Y = F × L A × ∆ L ,where letters have their usual meaning. This modulus is the ratio of stress and strain.