Exam Lessons Further Mathematics Physics

Moments (Torque) of a Force and Principles of Moments

Definition of Moment of a Force

Principles of Moments

Application of the Principle in Solving Problems


Moments of a Force:

The moment of a force about a reference point is defined as the product of the force and the force arm.  Moment of a force is a vector quantity and its units is Nm.

The direction of movement or sense of movement about the point is duly considered.

The object can move in clockwise moment and ant-clockwise moments about the given point.

Centre of Gravity:

The centre of gravity of a uniform plank or rod is the midpoint of the plant or rod

balance- centre of gravity the lower the centre of gravity= higher balance  | Physics courses, Physics, Gravity


A uniform beam PQ of length 100cm and of weight 35N lies on a support 40cm from the end P. Weights 54N and W are attached to the ends P and Q respectively to keep the beam in equilibrium. Find the value of W, to the nearest whole number.


Read Rotational Equilibrium and Principle of Moments. Page 178-185 of Further Mathematics Project  III.