After reading previous entry and understanding the meaning of stress and strain, how to apply Hooke’s law to elastic solids, you should try to solve next exercises.
EXERCISE 1: A steel wire has a length of 25 m and its cross-sectional area is 6 mm × 0.8 mm. Considering the effect of its own weight negligible, calculate the strain and the change in length when we applied a tension force of 6 kp. Young’s modulus of steel is 2.1×10^6 kp/cm^2.
EXERCISE 2: Determine the elongation of a bar of uniform cross section S and length L which is hanging and subjected to its own weight.