moments

• what is a moment?

  the rotational or turning effect of a force
• explain moments in a spanner:

  1. apply downwards force to the end of the spanner that's tightening something
  2. instead of the whole spanner moving downwards, the spanner will just turn around the central point (pivot)
  3. this turning effect is referred to as the moment
• what is the perpendicular distance?

  the distance between the pivot and the place where the force is being applied (e.g. the end of the spanner)
• how do you get the biggest moment possible?

  apply a big force far away from the pivot
• what do levers do?

  transmit the turning effect of a force
• what are some examples of levers?

  hammer, spanner, scissors
• how are forces applied to levers?

  1. we apply an input force
  2. this creates an output force somewhere else
• what happens if the input and output forces are on different sides of the pivot (e.g. scissors)?

  the forces will act in different directions
• what happens if the input and output are on the same side of the pivot (e.g. wheelbarrow)?


  they will both act in the same direction
• what does it mean that the output force is generally closer to the pivot?

  its a larger force
• what is the whole point of levers?

  we are able to get a large output force with a relatively small input force
• what is the role of gears?

  transmitting turning effects
• explain how gears of a car work:

  1. we have gear A and gear B
  2. gear A is connected to the car engine
  3. gear B is connected to the wheels
  4. since the two gears are interlocking, any rotation of gear A will cause gear B to rotate as well
  5. the gear system allows the turning effect of the engine to be transmitted to the wheels