4. the hubert h. humphrey metrodome in minneapolis, minnesota opened in 1982 at a cost of $55 million. to prepare for the footings, etc. 300,000 cubic yards of dirt were removed. its inflatable roof covers 10 acres and its interior column is 60 × 106 cubic feet. during construction, 40× 103 cubic yards of concrete, 11.9 × 103 tons of reinforcing steel and 5 × 102 tons of structural steel were utilized. the roof material includes an outer layer of teflon-coated fiberglass and an inner layer of woven fiberglass. given this information, answer the following: a. if removed evenly over the 10 acres, how deep of a hole would be formed as a result of the excavation? b. what is the total mass of the concrete and steel in lbm? c. if the two-layer fiberglass roofing material has a mass of 0.6667 lbm/ft2, what is the total mass of the roof? d. if 10 inches of wet snow collected on the roof as happened in 1982, what is the added mass to the roof? assume 1 inch of water equals 10 inches of snow.