the lever:a lever is like a teeter totter for example: a ruler with an eraser underneath for a fulcrum the magnets on one end are the load and push on the other end and that is your force.
levers are great for opening the door but you need to use effort to do so or else it will not work.
cranes,trains and lots of other machines have levers to operate them.
to control them and how they move in a system of wires and controls
Write something about yourself. No need to be fancy, just an overview.
Wheels And Pulleys