Machine Facts



  • A machine is a device that makes doing work easier by reducing the effort needed to move something.
  • There are two forces involved in every machine: the Load that the machine has to overcome and the effort used to move the load.
  • The amount that a machine reduces the effort needed to move a load is called the Mechanical Advantage. This tells you how effective a machine is.
  • Basic machines include levers, gears, pulleys, screws, wedges and wheels. More elaborate machines, such as cranes, are built up from combinations of these basic machines.
  • Machines cut the effort needed to move a load by spreading the effort over a greater distance or time.
  • The distance moved by the effort you apply, divided by the distance moved by the load, is called the Velocity Ratio (VR).
  • If the VR is greater than 1, then the Effort moves farther than the Load. You need less effort to move the load, but you have to apply the effort for longer.
  • The total amount of effort you use to move something is called Work. Work is the force you apply multiplied by the distance that the load moves.
  • One of the earliest machines still used today is a screw-like water-lifting device called a dalu, first used in Sumeria 5500 years ago.
  • One of the world’s biggest machines is the SMEC earthmover used in opencast mines in Australia. It weighs 180 tones and has wheels 3.5 m high.