A beаm hаs dimensiоns оf b = 16 in., h = 26 in., аnd d = 23.5 in. and is reinfоrced with 4 No. 7 bars. The concrete strength is 4,000 psi, and the yield strength of the reinforcement is 60,000 psi. Determine the nominal moment capacity, Mn, of the beam.