A class -1 lever has its fulcrum located somewhere between the effort and the load. The direction of force is changed with this type of lever. Applying effort downward moves the load up and applying effort upward moves the load down.Examples of class -1 levers that you may be familiar with are the playground seesaw, a crowbar, scissors, and pilers.

Machines

A lever is a rigid bar that rests on a fulcrum (a fixed point) . Something or someone must put force (push or pull) on a lever to make it work. The farther the force is from fulcrum, the easier it is to work with the lever. Levers may change the direction as well as the amount of force. There are three classes(kinds) of levers.