Final answer:
The question incorrectly requests the endurance limit of steel in relation to a static load problem. Endurance limit pertains to fatigue under cyclic loading, not static loading. Calculating the rod's diameter to support a truck's weight without excessive stretching involves using yield strength or tensile strength, not endurance limit.
Step-by-step explanation:
The endurance limit is not directly specified in the question about AISI 1020 CD steel, but rather the question addresses the necessary diameter of a steel rod to support the weight of a 2.5 × 104-kg truck without stretching more than 1.0 cm. The endurance limit is a property of a material that represents the maximum stress that can be applied indefinitely without leading to failure. However, the question seems to be mixing the concepts of static load bearing and material fatigue, which involves the endurance limit.
For a steel rod that supports a static load, such as a truck passing over it, we would typically be considering the yield strength or tensile strength, not the endurance limit, which pertains to cyclic loading. To calculate the required diameter based on a static load, one would need to apply principles from statics and strength of materials, and use the yield strength or ultimate tensile strength of AISI 1020 CD steel along with formulas that relate stress, force, and deformation to determine the appropriate diameter of the rod.