a) Moments

a) moment of force; moment = Fx

c) the principle of moments

moment = the turning effect of a force about a point

M = Fx

• moment of a force (Nm) = force acting on an object (N) × perpendicular distance between the force and the pivot (m)

  • perpendicular distance = the distance (between the force and the pivot) at which the angle between it and the force is 90°

  • pivot = the point at which an object turns

equilibrium = the state of a system having zero resultant force and zero net moment

• for a system in equilibrium → sum of upwards forces = sum of downwards forces

the principle of moments = for a system in equilibrium → sum of anticlockwise moments = sum of clockwise moments

• anticlockwise moment = the moment that causes the object to turn anticlockwise

• clockwise moment = the moment that causes the object to turn clockwise