Answer :
To determine the allowable uniform load per unit length for a beam with a maximum stress limit of 20,000 psi, one must consider the beam's dimensions, properties, and support conditions. Specific engineering calculations are required to relate the stress to the maximum load the beam can support.
To determine the allowable uniform load w per unit length of the beam, we must consider the maximum allowable stress in tension or compression, which is given as 20,000 psi. This stress limit relates to the failure conditions of the beam's material under load and will govern the design of the beam to ensure that it does not exceed this stress under the maximum expected load. The calculation of w will depend on other factors such as the beam's length, cross-sectional area, moment of inertia, and support conditions. These factors affect the distribution of stress within the beam when a load is applied. Using concepts such as bending moment, shear force, and deflection, one can relate the given stress limit to the amount of load the beam can support without failing. Engineering formulas for calculating the moment due to a uniform load, such as the bending moment formula M = wL2/8 for a simply supported beam, can be applied here. Note that a proper design would also consider factors like safety factors, the material's yield stress, and the specific loading conditions.