Levers and gears: Forces: Physics: GCSE (9:1)

• Force multiplier


  Something that is used to increase the effect of a force and is used to move large or heavy objects e.g. levers and gears
• Lever


  A simple machine consisting of a pivot, an effort and a load
• Pivot


  The point around which something can rotate or turn
• Effort


  The force used to move a load over a distance
• Load


  The overall force that is exerted by an object on a surface
• First-class lever


  When the pivot is in the middle with the effort and load on either side e.g. a see-saw

  
• Second-class lever


  When the load is in the middle with the pivot and effort on either side e.g. a wheelbarrow

  
• Third-class lever


  When the effort is in the middle with the pivot and load on either side e.g. tweezers, cooking tongs

  
• Gears


  Wheels with toothed edges that rotate about an axle or shaft

  
• Teeth (of a gear)


  The teeth of one gear fit into the teeth of another gear meaning one gear turns the other

  
• Direction of rotation of gears

  Where the gears meet, the teeth must both move in the same direction which means that the gears rotate in opposite directions

  
• What happens when a large gear is driven by a smaller one

  The large gear will rotate slowly but will have a greater moment than the smaller gear

  
• What happens when a small gear is driven by a larger one

  The small gear will rotate quickly but will have a smaller moment than the larger gear