First and Second-Class Lever

Simple machines are devices that transfer power and mechanical movement from one body to another. In this way, they can change the direction of force, transmit its position and multiply the magnitude of that force.

The body on which we use force through a simple machine is called the load.

The lever is a rod rotating around a solid axis (a fulcrum). A second-class lever is the lever in which both the weight and the working force (effort) act on the same side of the axis of rotation (the fulcrum is at the end).

The bottle opener is a second-class lever. However, there may also be openers that are based on a first-class lever (where the fulcrum is in between the load and the energy moving the load, such as pliers or scissors).