Moment

• Moment is the product of force times distance
• what is moment

  Moment is the rotational effect of force
• Give examples of where moment is used in everyday life

  In hinges and the centre point of a sea saw
• Moment of force is also called torque, it is the turning effect of a force on an object
• SI unit of torque 


  Nm
• If the distance is smaller we need more force to generate the torque
• Moment has 2 directions.

  1. clockwise
  2. anticlockwise
• Moment is a vector quantity
• Equilibrium


  Balance or to be balanced
• Two conditions of Equilibrium

  1. If a body is in equilibrium then sum of forces or resultant force is 0
  2. sum of clockwise moment is equal to sum of anti clockwise moments or sum of torque is 0
• In static equilibrium, all forces are stationary (not moving) and there is no acceleration.
• The centre of gravity is the point where the weight of an object acts as though it were concentrated. It is also known as the centre of mass.
• A system can only have one point of rotation at any given time. This means that if an object rotates about two points simultaneously it will not be able to maintain its balance and will fall over.
• A pivot is a fixed point around which something turns or rotates. A lever is a rigid bar that moves about a pivot. When a lever is used to move an object, the effort applied by the person turning the handle causes a load to move.
• Centre of Gravity is the point at which the whole weight of an object can be considered to act. The line through this point passes through the middle of the object.
• Torque is the turning effect produced by a force acting through a distance from the pivot point. Torque causes objects to turn or twist.
• Newton's second law states that the rate of change of momentum of an object is directly proportional to the resultant force acting on the object and takes place in the direction of the resultant force.
• When a force is applied to an object causing it to rotate, the direction of the moment depends on whether the force is acting towards or away from the axis of rotation.