Hooke's Law To use Hooke's law and the definitions of stress and strain to calculate unknown values for linear elastic deformation of a rod. A material undergoing uniaxial elastic deformation obeys Hooke's law. This law states that the stress is proportional to the strain, or = Ee. The proportionality constant is called Young's modulus, or the modulus of elasticity. Stress is a measure of force per unit area. When the stress is uniform over a region, it can be calculated using = F where F is the load supported by the region, and A is the area of the region. Strain is a measure of change in length per unit length, or = L Part A Change in length < 2 of 6 Review A circular rod with a gage length of 4 m and a diameter of 3 cm is subjected to an axial load of 55 kN. If the modulus of elasticity is 200 GPa, what is the change in length? Express your answer with appropriate units to three significant figures. View Available Hint(s) AL= 4 mm ? Figure 1 of 1 Submit Previous Answers (MPa) Incorrect; Try Again 300 200 100 Part B Modulus of elasticity A circular rod with a length of 3.4 m and a diameter of 3 cm is subjected to an axial load of 50 kN. If the resulting change in length is 3.94 mm, what is the modulus of elasticity? Express your answer with appropriate units to three significant figures. View Available Hint(s) E 0.001 0.002