A solid rectangular simply supported timber beam 6 in. wide, 20 in. deep, and 10 ft long carries a concentrated load of 16,000 lb at midspan. Use nominal dimensions
(a) Compute the maximum horizontal shear stress at the neutral axis.
(b) Compute the shear stress 4 in. and 8 in. above and below the neutral axis. Neglect the weight of the beam.