A two-stepped bar fixed at one end and subjected to an axial force F at the other end is shown in Figure 3. The length of step i is l, and its cross-sectional area is A, All the steps are made of the same material with Young's modulus E = E, i = 1, 2 i. ii. 111. Find the spring constant (or stiffness) k; of step i in the axial direction (i = 1,2). Find the equivalent spring constant (or stiffness) of the stepped bar, keq in the axial direction so that F = keqx Indicate whether the steps behave as series or parallel springs. A 4 A -12 Figure 3: A stepped bar subjected to axial force