Phys: 3.3 (Moments)

• What is a moment in physics?

  A moment is the turning effect of a force.
• What is the equation used to calculate the moment of a force?

  Moment of a Force = Force x Distance
• What distance must be used when calculating a moment?

  The perpendicular distance between the line of action of the force and the axis of rotation.
• What is the unit of a moment?

  Nm
• What is the principle of moments?

  For an object to be in equilibrium, the sum of the clockwise moments about a point must be equal to the sum of the anticlockwise moments.
• What is an object’s centre of gravity?

  The single point through which the object’s entire weight can be said to act.
• What will occur if the line of action of an object’s centre of gravity lies outside its base?

  The object’s weight will produce a resultant moment and so if unsupported, the object may topple.
• What are the key concepts related to moments in physics?

  • A moment is the turning effect of a force.
  • Moment of a Force = Force x Distance.
  • Use the perpendicular distance for calculations.
  • Unit of moment is Nm.
  • Principle of moments: clockwise moments = anticlockwise moments for equilibrium.
  • Centre of gravity: point where weight acts.
  • If the centre of gravity lies outside the base, the object may topple.