This download includes a detailed lesson plan and a PowerPoint to aid the delivery of a lesson on the Principle of Moments. This is the first of two lessons on moments, the other one being "More on Moments"
Moment of a force about a point
Couple as a pair of equal and opposite coplanar forces
Moment of a couple defined as:
moment = force X perpendicular distance between the lines of action of the forces
Principle of moments