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What is a wheel and axle?

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Quick answer

A wheel and axle is a simple machine made of a large wheel attached to a smaller rod (the axle) that turn together. Applying a small force to the rim of the big wheel produces a much larger turning force at the axle — or lets the axle move things a long way with each turn.

Key things to understand

  1. The wheel and axle are fixed together and rotate as one unit.
  2. A small force on the large wheel creates a bigger force at the smaller axle (more turning power).
  3. Used the other way, turning the axle moves the wheel's rim a long distance quickly.
  4. Doorknobs, steering wheels, screwdrivers, and bicycle wheels all use this machine.
  5. The bigger the wheel compared with the axle, the greater the mechanical advantage.

People also ask

How does a wheel and axle work?
The wheel and axle are joined and spin together. A small force applied around the large wheel turns into a much greater force at the smaller axle — or lets the rim travel far with each turn.
Is a wheel and axle the same as a wheel?
Not quite. A simple rolling wheel reduces friction; a wheel and axle is a machine where the two are fixed together, so turning one turns the other, multiplying force or distance.
What are examples of a wheel and axle?
Doorknobs, steering wheels, screwdrivers, ferris wheels, bicycle wheels, and the gears inside many machines.

Part of the guide: Everyday Machines →