Moments

• The moment of a force is the product of the force and the perpendicular distance between the axis of rotation and the line of action of the force
• The moment of the force is calculated using the equation: moment = force x perpendicular distance between the line of action of the force and the axis of rotation.
• Moment = Fd. The unit of a moment is Nm
• The principle of moments states that if a system is in equilibrium, the sum of the clockwise moments must equal the sum of the anticlockwise moments
• When a tap is turned on or off, it is usual to apply a pair of equal forces in opposite directions at each end of the tap head. The resultant moment is called a couple. Couple = F x 𝑥 + F x 𝑥 = 2(F x 𝑥) = magnitude of each force x perpendicular separation of their lines of action, where 𝑥 equals d.

  
• In engineering, the turning effect due to two or more forces is usually referred to as the torque. The unit of torque is Nm