A simply supported beam spans 20 ft and carries a uniformly distributed dead load of 0.8 kip/ft, including the beam self-weight, and a live load of 2.3 kip/ft. Determine the minimum required plastic section modulus (Zx) and select the lightest-weight W-shape to carry the moment. Consider only the limit state of yielding and use A992 steel.

Awall of 0.5m thickness is to be constructed from a material which has average thermal conductivity of 1.4 w/mk. the wall is to be insulated with a material having an average thermal conductivity of 0.35 w/mk so that heat loss per square meter shall not exceed 1450 w. assume inner wall surface temperature of 1200°c and outer surface temperature of the insulation to be 15°c. calculate the thickness of insulation required.