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← ⚛️ Physics · usually met in Std 5-9

Simple machines

Lever, pulley, wheel and axle, inclined plane, wedge and screw. None of them reduces the work; each changes the deal you get.

First classfulcrum in the middle see-saw, crowbar, scissorsSecond classload in the middle wheelbarrow, nutcrackerThird classeffort in the middle tongs, your own forearm ▲ effort ■ load ◣ fulcrum A ramp: a gentler push, over a longer distance. None of them reduces the WORK. Each trades force against distance, and friction takes its cut. There is no machine that gives you something for nothing, however clever the drawing.
Drawn for Star Student.

A simple machine trades force against distance. A crowbar lets you lift a weight you could never lift directly, but your end of it has to travel much further. A ramp lets you raise a drum with a gentler push, over a longer path. A pulley can change the direction of your pull, which matters when you are standing on the ground and the load must go up.

What none of them can do is give you energy for nothing. Work is force times distance, and apart from what friction wastes, the work you put in is the work that comes out. Every machine in a factory, however complicated, is a combination of these six ideas with the friction engineered down.

Worth knowing

  • Mechanical advantage is the load divided by the effort — how many times the machine multiplies your push.
  • A screw is an inclined plane wrapped round a cylinder.
  • Scissors are two levers and two wedges working together.

Want to see it moving? Search YouTube for “Simple machines” ↗ — we send you to the search rather than to one video, because a link to one video eventually rots.

See also

⚛️ Energy⚛️ Friction⚛️ Newton's laws of motion

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Last gone through: 1 October 2026 · How these entries are written

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