moments levers and gears

• What is a moment?

  A moment is the turning effect of a force
• What causes a larger moment to occur?

  A larger force

  
  

  A larger distance
• Give 5 examples of moments.

  - wheelbarrow

  - a man using a crowbar

  - seesaw

  - crane

  - hammer being used to remove a nail
• What is the equation to calculate the moment (Nm) of a force?

  moment (Nm) = force x distance

  M = Fd

  
• What is important about the distance when calculating a moment?

  - distance has to be perpendicular from the pivot to the line of action of the force
• What is involved in a balanced object?

  - if an object is balanced, the total clockwise moment about a pivot equals the total anticlockwise moment

  
• Why do some objects topple over?

  - normally, the weight of the object acts directly down from the centre of mass

  - if we tilt the object, there comes a point where the line of action of the weight lies outside the base of the object. Now there is a resultant (unbalanced) moment acting on the object, causing the object to topple.
• What are levers?

  Increase the distance at the pivot at which the force is applied

  
  

  Levers make it easier to do work

  
  

  Lift a load/ turn a nut
• What do gears do?

  Transmit rotational effects

  
  

  Their teeth interlock - causing one to turn will cause another to turn

  
  

  Larger gear turns slower than smaller gear
• How is it identified if an object is balanced and won't turn?

  If the anticlockwise and clockwise moments are equal