Moment of a force

Gap-fill exercise

Fill in all the gaps.
   direction      Distance      down      Equilibrium      Force      magnitude      metre      Newton      opposite      parallel      Perpendicular      turning   
As well as causing an object to accelerate, a force may cause a body to turn or rotate, i.e. a force can have a effect.

To quantify this turning effect we have the following relationship, called The Moment of a Force:

Moment of a Force = Force × Perpendicular

The unit of moment of a force is the Metre (Nm).


Conditions for Equilibrium of an object under Co-planar Forces
If an object is in equilibrium then:

1. The vector sum of the forces in any is zero.

(forces up = forces )

2. The sum of the moments about any point is zero.

(Total sum of clockwise moments = Total sum of anti clockwise moments)


Moment of a Force = ×



A couple

Two forces with the same acting in directions are called a couple.

Unit of a couple Newton

Example: Turning a steering wheel (or two people on opposite ends of a revolving door).


Torque

The Moment of a couple is known as Torque

Moment of a couple (Torque) T = x Distance (between the two forces – Not distance to the middle)

T = F × d


Mandatory Experiment:


To verify the Laws of for a set of coplanar Forces.