Notes From December 2nd

Wedge - A modified incline plane

* (Wedge moves, but inclined plane stays in place)
1. Can be used to split or pierce things.
2. Can be used to keep something in place

  • 2 Main Types of wedge
    • Single wedge
    • Double wedge
  • Examples
    • Fork
    • shovels
    • axes
    • picks
    • keystone
  • Mechanical advantage = length/thickness of the big end.


1. Simple Pulley

  • Used to lift or move things in vertical directions.
  • Consists of one or more pulley and a belt, or rope, or cable.

2. Conveyor Belt

  • Output force is the weight of the object.
  • Input force is the force that pulls down on the weight or the cable.


First Class

  • Fulcrum is between the load and the effort (and underneath them)
  • Makes it easier to lift a load(if the fulcrum is closer to the load) or make it lift higher and faster (if the fulcrum is closer to the effort)
  • Examples
    • Oar
    • Seesaw
  • Mechanical Advantage =distance from the fulcrum to effort / distance from the folcurm to the load

Second Class

  • Fulcrum is on the edge, the load is in the middle, and the effort is on the opposite end of the Fulcrum.
  • Example
    • Wheel Barrow
    • Push ups
    • Crow bars

Third Class

  • Fulcrum is still on the end, but the effort is in the middle and the load is on the end.
  • Applied force must be more than the load.
  • Mechanical advantage is that it moves the load faster and higher.
  • Examples
    • Diving Board
    • Arm

Inclined Plane

  • Make transporting something easier (you can raise something easier, but you must push it over a large distance)
  • Normal forces are always perpendicular to a surface
  • Examples
    • Wheel chair ramps
    • ski jumps
  • You can overcome a big resistance by applying a smaller force over a longer distance


  • Mechanical advantage = circumference / pitch
  • Pitch is the distance between each thread

Wheel and Axle

  • Wheel rotates around a center point (fulcurm)
  • A large wheel rotates around a small axle
  • Maybe the most important invention …
  • Mechanical Advantage = Radius of the Wheel/Radius of the axle
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