This document contains lecture material on moments and couples from a engineering mechanics course. It includes: - Definitions of moment as the turning effect of a force and how to calculate moment magnitude using the perpendicular distance from the axis (moment arm). - Details on sign conventions and using the right hand rule to determine moment direction. - An explanation of Varignon's theorem which states the sum of all individual moments equals the moment of the resultant force. - Examples of calculating moments using scalar and vector methods, as well as resolving force systems into equivalent force-couple systems. - The definition of a couple as two equal and opposite parallel forces separated by a perpendicular distance, and characteristics such as couple