Question

A steel W18 x 55 section weighs about 55 pounds per lineal foot (81 kilograms per lineal meter). Guess which of the following weighs the same per length: 3-inch (7.6-centimeter) diameter steel rod, 4-inch (10.2-centimeter) square steel bar, or a 10-inch (25.4-centimeter) diameter standard steel pipe.

Answer

The density of steel is 490 pounds per cubic foot. A 4-inch square bar weighs just under 55 pounds per lineal foot. The 3-inch diameter bars weighs 24 pounds per foot while the 10-inch pipe weighs 40 pounds per foot.

(The density of steel is 7850 kilograms per cubic meter. A 10.2-centimeter square bar weighs just under 81 kilograms per lineal meter. The 7.6-centimeter diameter bars weighs 35.7 kilograms per meter, while the 25.4-centimeter pipe weighs 59.5 kilograms per meter.)