Which statement is correct regarding torque units?

• A. One foot-pound equals twelve inch-pounds
• B. One foot-pound equals six inch-pounds
• C. One foot-pound equals twenty-four inch-pounds
• D. One foot-pound equals one inch-pound

Answer: (A)

Torque is a force applied at a distance, so the numeric value depends on the distance unit. Since 1 foot equals 12 inches, a torque of 1 pound-force at 1 foot is 12 pound-force inches. So one foot-pound equals twelve inch-pounds. The other options don’t fit because they correspond to different distances: six inch-pounds is 0.5 foot-pounds, twenty-four inch-pounds is 2 foot-pounds, and one inch-pound is 1/12 of a foot-pound. To convert the other way, 1 in-lbf equals 1/12 ft-lbf.