Open top steel box weight problem: four oak timbers that measure 8 inches by 8 inches by 9 feet weigh approximately how much?

• A. 960 lbs
• B. 992 lbs
• C. 1,040 lbs
• D. 980 lbs

Answer: (B)

Weight is found by multiplying the timber’s volume by the wood’s unit weight. Each timber has a cross-section of 8 in by 8 in, giving 64 square inches of area. With a length of 9 feet (108 inches), the volume per timber is 64 × 108 = 6,912 cubic inches. For four timbers, total volume is 27,648 cubic inches, which equals 16 cubic feet (since 27,648 ÷ 1,728 = 16). Oak typically has a unit weight around 60–62 pounds per cubic foot; using 62 lb/ft^3 gives 16 × 62 = 992 pounds. So the approximate weight is about 992 pounds. If you used a slightly different oak density you’d land in a nearby range (roughly 960–1,040), but 992 pounds is the closest estimate.