A wheel of diameter d and width w carrying a load F rolls on a flat rail. Assume that Figure 3-40, which is based on a Poisson's ratio of 0.3, is applicable to estimate the depth at which the maximum shear stress occurs for these materials. At this critical depth, calculate the Hertzian stresses x, y, z, and max for the wheel. [Hint: Refer to Contact Stresses / section 3-19. Start by computing the half-width b and max. pressure (pmax). Refer to Fig. 3-40 and be sure to read the caption. Consult table A-5 for properties of carbon steel and cast iron.] Problem Number d 3-156 150 mm w 40 mm F Wheel Material Rail Material 2 kN Steel Cast iron