Mechanical Properties of Solids – Solutions

1) A steel wire of length 4.7 m and cross sectional area 3.0 x 10^-5 m² stretches by the same amount as a copper wire of length 3.5 m and cross sectional area of 4.0 x 10^-5 m² under a given load. What is the ratio of the young’s modulus of steel to that of copper?

Solution:

Let the Young’s modulus of the steel wire be Ys and that of copper be Y_c.

Young’s modulus of a wire, Y = Fl/Ae

As F, e are same for both the wire

=  x A/

=  x

Thus, the ration of the Young’s modulus of steel to that of copper is 1.79:1.

2) Figure 9.11 shows that strain curve for a given material. What are?