5.4 Moments, Levers and Gears

• Moment


  Alternative name for the turning effect of a force
• Calculating the moment of a force

  1. Moment of force = Force x Distance

  2. Moment (Nm)

  3. Force (N)

  4. Distance (m)
• Distance measurement for moment

  The perpendicular distance from the pivot to the line of action of the force
• If an object is in equilibrium

  The clockwise moments are equal to the anticlockwise moments
• Parts of a lever system

  • Load
  • Effort
  • Pivot
• Lever as a force multiplier

  If the distance between the effort and pivot is greater than the distance between the pivot and load, the force applied on the load is greater than the effort force
• The moment on both the effort and load must be the same
• Moment of a gear wheel


  Determined by the size of the wheel
• Larger gear driven by smaller gear

  The larger wheel will rotate more slowly but will also produce a larger moment