When you push or pull with a simple machine, you are applying a force and doing work. And, if you get more force out of a machine than you put into it, then that machine has a mechanical advantage.

Different gears like spur, bevel, worm and wormwheel, rack and pinion, meshed gears, and threaded bars serve various purposes. When selecting a gear system, consider speed, direction, force, space, ...

A simple machine is a mechanical device that changes the direction or magnitude of a force. In general, they can be defined as the simplest mechanisms that use mechanical advantage (also called ...