Galvanized steel with a coefficient of thermal expansion of 0.0000067 will increase in length by how much for a 10-foot length with a 100°F temperature rise?

Galvanized steel with a coefficient of thermal expansion of 0.0000067 will increase in length by how much for a 10-foot length with a 100°F temperature rise?

• A. 5/64 inch
• B. 1/8 inch
• C. 3/64 inch
• D. 1/4 inch

Answer: (A)

When a material heats up, it lengthens in proportion to its original length, the temperature rise, and its coefficient of thermal expansion. Use ΔL = α × L0 × ΔT. With α = 0.0000067 per °F, the original length L0 = 10 feet = 120 inches, and a temperature rise ΔT = 100°F, the change in length is ΔL = 0.0000067 × 120 × 100 = 0.0804 inches. That is about 0.080 inch, which is closest to 5/64 inch (0.078125 in). The other options differ more noticeably from 0.0804 inches, so they don’t fit as well.

When a material heats up, it lengthens in proportion to its original length, the temperature rise, and its coefficient of thermal expansion. Use ΔL = α × L0 × ΔT. With α = 0.0000067 per °F, the original length L0 = 10 feet = 120 inches, and a temperature rise ΔT = 100°F, the change in length is ΔL = 0.0000067 × 120 × 100 = 0.0804 inches. That is about 0.080 inch, which is closest to 5/64 inch (0.078125 in). The other options differ more noticeably from 0.0804 inches, so they don’t fit as well.