What is the term for the product of the weight of an item multiplied by its arm, used in weight-and-balance calculations?

• A. Moment
• B. Moment arm
• C. Moment index
• D. Monocoque

Answer: (A)

In weight-and-balance work, the moment is the product of an item’s weight and its arm, and it captures how much that weight tends to rotate the aircraft about the reference datum. The arm is the horizontal distance from the datum to the weight’s line of action, so multiplying weight by that distance gives the turning effect in units like pound-feet (lb-ft) or newton-meters (N·m). For example, a 100‑lb item located 5 ft from the datum produces a moment of 500 lb-ft. All moments are summed to get the total moment, and the center of gravity is found by dividing that total moment by the total weight. The other terms don’t fit: a moment arm is just the distance itself, a term like moment index isn’t used in this context, and monocoque refers to a type of aircraft construction, not to weight and balance.