2006-10-02 10:50:18 · 2 answers · asked by Anonymous in Science & Mathematics ➔ Mathematics
multiply by 7
480 * 7 = 3360 lbs
2006-10-02 10:52:57 · answer #1 · answered by borscht 6 · 0⤊ 1⤋
Do you mean 480 lbs per linear foot or 480 lbs per cubic foot? I think you must mean the latter. (The first would simply be 7 x 480, but I don't think a 7 foot steel rod (2") diameter would weigh that much). Looking up the density of steel, 480 lbs. per cubic foot makes more sense.
You would first need to figure the volume of the rod and multiply it by the density.
The volume of a cylinder is area of the circle times the length.
The radius is 1/12 foot (1 inch), so the area of a cross section of pipe is pi/144 sq. feet.
Altogether the volume is 7/144 pi cu. feet. This is approximately 0.152 cu. feet. Multiply this times 480 lbs / cu. ft. and you get approximately 73.3 lbs.
This seems like a more reasonable answer.
2006-10-02 11:02:41 · answer #2 · answered by Puzzling 7 · 0⤊ 0⤋