Topic 9 - Moments

• Moment


  Alternative name for the turning effect of a force
• Moment of force


  Equation: Moment = Force x Distance

  Units: Moment (Nm), Force (N), Distance (m)
• Distance measurement used when calculating a moment

  The perpendicular distance from the pivot to the line of action of the force
• Equilibrium


  The clockwise moments are equal to the anticlockwise moments
• Levers


  • They increase the perpendicular distance of the force from the pivot, so decrease the force needed to produce the same moment
• Lever example


  • 20N force, 4m distance

  10N force, 2m distance

  The object remains in equilibrium as the clockwise and anticlockwise moments are equal
• How levers decrease force required to lift something

  Levers use a pivot point and the concept of moments to reduce the force. The further you are away from the pivot point, the less force you need to lift the object up.
• Lubricating levers/gears


  Improves efficiency by reducing resistance and energy dissipation (as heat) from frictional forces