Question

Which of the following choices should Fumiko and Sierra take as the best estimate for the elastic limit of this material?

0.001 MPa
0.004 MPa
0.008 MPa
0.01 MPa

Answer 1

For relatively small stresses (force per cross-sectional area), a bar is elastic; it returns to its initial length when an applied force is removed. The elastic limit of a substance is defined as the maximum stress that can be applied to the substance before it becomes permanently deformed (plastic) and does not return to its initial length. It is possible to exceed the elastic limit of a substance by applying a sufficiently large stress. When the stress exceeds the elastic limit, the object is permanently distorted and does not return to its original shape after the stress is removed. The elastic limit can be found by plotting stress (F/A) vs. strain (ΔL/L), and is the value of the stress for which the curve begins to deviate from a straight line. Consider the following data for an elastic solid under an applied tension force.
Stress [MPa] Strain Stress [MPa] Strain
0.001 0.100 0.006 0.431
0.002 0.200 0.007 0.435
0.003 0.300 0.008 0.439
0.004 0.400 0.009 0.443
0.005 0.425 0.01 0.445

Which of the following choices should Fumiko and Sierra take as the best estimate for the elastic limit of this material?
0.001 MPa
0.004 MPa
0.008 MPa
0.01 MPa

Answer 2

the answer was 0.004Mpa