A lever is a simple "machine" known since ancient times.
Components:
(1) lever
(2) fulcrum (pivot)
(3) load (mass being moved)
(4) effort (force applied to move load)
length of the lever =
= (distance between load and fulcrum) + (distance from fulcrum to effort)
(load) * (distance between load and fulctrum) =
= (effort) * (distance between fulcrum and effort)
