What is a mechanism?

The moving parts of a bicycle are examples of everyday mechanisms that make life easier and more enjoyable:

• The chain of a bicycle transfers motion to the back wheel.
• The bar of a seesaw forms a lever that we can use for fun.
• The gears inside old-fashioned clocks let us measure time.
• The pulley system above a well helps us to bring up water.

They make work easier because they transmit and transform force and motion.
All of these mechanism require an input force and motion from some type of source. Mechanisms transmit motion and force to receptors that finally perform the work.
This is the output force and motion.

-Output: the power or energy supplied by a device.
-Input source: what we put in...