Question

Solve:find stress required to increase length of a steel wire by 0.1 percentage(y=210 gpa)

Answer 1

In continuum mechanics, stress is a physical quantity that expresses the internal forces that neighboring particles of a continuous material exert on each other, while strain is the measure of the deformation of the material. For example, when a solid vertical bar is supporting an overhead weight, each particle in the bar pushes on the particles immediately below it. When a liquid is in a closed container under pressure, each particle gets pushed against by all the surrounding particles. The container walls and the pressure-inducing surface push against them in reaction. These macroscopic forces are actually the net result of a very large number of intermolecular forces and collisions between the particles in those molecules. Stress is frequently represented by a lowercase Greek letter sigma.

Answer 2

Length should be increased by 50%
e = L/2

F = YAe / L
= (2 × 10^11 × 0.1 × 10^-6 × L/2) / L
= 10^11 × 10^-7 N
= 10^4 N
= 10 kN

Force required is 10 kN