Be able to calculate the moment of a force about a point or axis.

Notation:
Units of moment are \(N~m\).

[Excludes: Vector treatment.]

Parallel and non-parallel coplanar forces

Understand that a rigid body is in equilibrium when the resultant force is zero and the sum of the moments about any one point is zero.

Equilibrium of rigid bodies

Understand that a system of forces can have a turning effect on a rigid body.

Notation:
Moment

Equilibrium of rigid bodies

Know that, for the purpose of calculating its moment, the weight of a body can be taken as acting through a point.

The point is the centre of mass of the body.
Questions will be restricted to cases where the centre of mass is given or can be found using symmetry or can be found from consideration of moments.

Notation:
Uniform

[Excludes: Finding the centre of mass of a composite body.]

Parallel and non-parallel coplanar forces