A 1/2 inch steel-walled empty cylindrical tank that is opened at one end weighs approximately how many pounds?

• A. 1,200
• B. 1,800
• C. 2,400
• D. 3,000

Answer: (B)

Estimating the weight of a hollow steel tank comes from the weight of the metal making the shell. For a thin-walled approximation, weight ≈ density × thickness × (area of side wall + area of the closed end). Steel density is about 0.284 lb/in^3.

Take a representative size: diameter 3 feet (radius 18 inches) and length 8.5 feet (102 inches), with wall thickness 1/2 inch. The side-wall volume is 2π r L t = 2 × π × 18 × 102 × 0.5 ≈ 5,762 in^3. The end-plate volume is π r^2 t = π × 18^2 × 0.5 ≈ 509 in^3. Total metal volume ≈ 6,271 in^3. Weight ≈ 6,271 × 0.284 ≈ 1,780 pounds, about 1,800.

So for a typical-sized empty steel tank opened at one end, around 1,800 pounds is a reasonable estimate.