5.4.3 Levers & Gears

Levers and Gears (Physics only)

Levers

Using a longer spanner:

• Increases the moment (turning effect).
• Reduces the amount of force you need to apply to turn something, like a nut or bolt.

• Increasing the length of the spanner increases the moment. By increasing the length of the spanner, we are increasing the size of the moment. This is because our perpendicular distance is effectively the length of the spanner (assuming the force is straight). We already know that increasing the perpendicular distance will increase the size of the moment, so we can do the same thing by making the spanner longer.
• Increasing the length of the spanner decreases the force needed. As well as increasing the moment, a longer spanner will decrease the force needed to act on an object.

Gear Interactions

• Gears can change speed, force, or direction by rotation.

• First Gear Supplying the Force:
  • Connected to a Gear with Fewer Teeth (Smaller Gear):
  • The second gear will turn faster.
  • With less force.
  • In the opposite direction to the first gear.
  • Connected to a Gear with More Teeth (Larger Gear):
  • Turns slower.
  • More force.
  • In the opposite direction.

Direction of Turn

• The second gear will always turn in the opposite direction.