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Inclined plane      
An inclined plane can be used to alter the effort and distance involved in doing work, such as lifting loads. The trade-off is that an object must be moved a longer distance than if it was lifted straight up, but less force is needed.
Machines
Ratchet
A ratchet is a device that allows a wheel to turn in only one direction. The ratchet wheel has specially shaped teeth. A bar on a pivot called the "pawl" is fixed above the ratchet wheel. The pawl slides over the teeth of the ratchet in one direction, but blocks the motion of the teeth if the wheel turns in the other direction.