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What is a simple machine?

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Quick answer

A simple machine is a basic device that makes work easier by changing the size or direction of a force. There are six classic types — the lever, pulley, wheel and axle, inclined plane, wedge, and screw — and almost every complex machine is built from combinations of them.

Key things to understand

  1. Simple machines don't reduce the total work needed — they trade force for distance, letting you use less force over a longer distance.
  2. The six classic simple machines are the lever, wheel and axle, pulley, inclined plane, wedge, and screw.
  3. They make tasks easier by changing how much force you apply or which direction you apply it.
  4. The factor by which a machine multiplies your force is called its mechanical advantage.
  5. Complex machines — bikes, cranes, cars — are just clever combinations of simple machines.

People also ask

What are the six simple machines?
The lever, wheel and axle, pulley, inclined plane, wedge, and screw. Each makes work easier by changing the size or direction of a force.
Do simple machines reduce the work you do?
No — they reduce the force needed, but you apply it over a longer distance, so the total work stays the same (friction makes it slightly more). They make hard tasks feel easier.
What is mechanical advantage?
It's how many times a machine multiplies your effort. A lever that lets you lift a load with half the force has a mechanical advantage of 2.

Part of the guide: Everyday Machines →